diff --git a/README.md b/README.md
index fec0884..fd26a1e 100644
--- a/README.md
+++ b/README.md
@@ -201,11 +201,16 @@ Defaults:
 
 ```javascript
 {
-  keepErrors: false
+  keepErrors: false,
+  singleError: false
 }
 ```
 
 - _keepErrors_: keep original errors. Default is to remove matched errors (they will still be available in `params.errors` property of generated error). If an error was matched and included in the error generated by `errorMessage` keyword it will have property `emUsed: true`.
+- _singleError_: create one error for all keywords used in `errorMessage` keyword (error messages defined for properties and items are not merged because they have different dataPaths). Multiple error messages are concatenated. Option values:
+  - `false` (default): create multiple errors, one for each message
+  - `true`: create single error, messages are concatenated using `"; "`
+  - non-empty string: this string is used as a separator to concatenate messages
 
 
 ## License
diff --git a/SPEC.md b/SPEC.md
index a949d82..9a41a22 100644
--- a/SPEC.md
+++ b/SPEC.md
@@ -93,10 +93,8 @@ Example:
 
 All errors that "errorMessage" keyword processes determined by keyword value, as described above.
 
-Each appearance of "errorMessage" keyword can generate either multiple or a single error message, depending on the option "multiple" (true/false, default is false?).  // DONE only multiple errors, TODO: single error
+Each appearance of "errorMessage" keyword can generate either multiple or a single error message, depending on the option "multiple" (true/false, default is false?).  // DONE
 
-If a single message is generated, option "separator" (a string, default is ', ' - same as in errorsText method) defines how to join multiple messages into a single string. // TODO
+If a single message is generated, option "separator" (a string, default is ', ' - same as in errorsText method) defines how to join multiple messages into a single string. // DONE
 
-Option "prefix" can be used to prepend error message with "property" name or "dataPath"? // TODO?
-
-Option "mode" determines whether the errors are replaced by "errorMessage" errors or they are kept ("replace"/"append", default is "replace"). // DONE replace, append - TODO
+Option "mode" determines whether the errors are replaced by "errorMessage" errors or they are kept ("replace"/"append", default is "replace"). // DONE
diff --git a/lib/dot/errorMessage.jst b/lib/dot/errorMessage.jst
index 540c651..328a0f5 100644
--- a/lib/dot/errorMessage.jst
+++ b/lib/dot/errorMessage.jst
@@ -69,6 +69,12 @@
   };
 #}}
 
+{{## def.em_errorMessage:
+  {{=$key}} in {{=$templates}}
+  ? {{=$templates}}[{{=$key}}] ()
+  : validate.schema{{=$schemaPath}}[{{=$key}}]
+#}}
+
 
 {{? it.createErrors !== false }}
   {{
@@ -86,6 +92,8 @@
       , $matches = '_em_matches' + $lvl
       , $isArray = '_em_isArray' + $lvl
       , $errors = '_em_errors' + $lvl
+      , $message = '_em_message' + $lvl
+      , $paramsErrors = '_em_paramsErrors' + $lvl
       , $templates = '_em_templates' + $lvl
       , $errSchemaPathString = it.util.toQuotedString(it.errSchemaPath);
   }}
@@ -162,25 +170,50 @@
             {{=$i}}++;
           }
         }
-        for (var {{=$key}} in {{=$errors}}) {
-          if ({{=$errors}}[{{=$key}}].length) {
-            var err = {
-              keyword: '{{=$keyword}}'
-              , dataPath: {{=$dataPath}}
-              , schemaPath: {{=$errSchemaPathString}} + '/{{=$keyword}}'
-              , params: { errors: {{=$errors}}[{{=$key}}] }
-              , message: {{=$key}} in {{=$templates}}
-                          ? {{=$templates}}[{{=$key}}] ()
-                          : validate.schema{{=$schemaPath}}[{{=$key}}]
-              {{? it.opts.verbose }}
-                , schema: validate.schema{{=$schemaPath}}
-                , parentSchema: validate.schema{{=it.schemaPath}}
-                , data: {{=$data}}
-              {{?}}
-            };
-            {{# def._addError:'custom' }}
+
+        {{? $config.options.singleError }}
+          var {{=$message}} = '';
+          var {{=$paramsErrors}} = [];
+        {{?}}
+
+          for (var {{=$key}} in {{=$errors}}) {
+            if ({{=$errors}}[{{=$key}}].length) {
+
+        {{? $config.options.singleError }}
+              if ({{=$message}}) {
+                {{=$message}} += {{? typeof $config.options.singleError == 'string' }}
+                  {{= it.util.toQuotedString($config.options.singleError) }}
+                {{??}}
+                  '; '
+                {{?}};
+              }
+              {{=$message}} += {{# def.em_errorMessage }};
+              {{=$paramsErrors}} = {{=$paramsErrors}}.concat({{=$errors}}[{{=$key}}]);
+            }
           }
-        }
+        {{??}}
+              var {{=$message}} = {{# def.em_errorMessage }};
+              var {{=$paramsErrors}} = {{=$errors}}[{{=$key}}];
+        {{?}}
+
+              var err = {
+                keyword: '{{=$keyword}}'
+                , dataPath: {{=$dataPath}}
+                , schemaPath: {{=$errSchemaPathString}} + '/{{=$keyword}}'
+                , params: { errors: {{=$paramsErrors}} }
+                , message: {{=$message}}
+                {{? it.opts.verbose }}
+                  , schema: validate.schema{{=$schemaPath}}
+                  , parentSchema: validate.schema{{=it.schemaPath}}
+                  , data: {{=$data}}
+                {{?}}
+              };
+              {{# def._addError:'custom' }}
+
+        {{? !$config.options.singleError }}
+            }
+          }
+        {{?}}
       {{?}}
 
       {{? $hasProperties || $hasItems }}
diff --git a/spec/options.spec.js b/spec/options.spec.js
index 7ca05ab..2a8b306 100644
--- a/spec/options.spec.js
+++ b/spec/options.spec.js
@@ -10,10 +10,13 @@ describe('options', function() {
 
   beforeEach(function() {
     ajv = new Ajv({allErrors: true, jsonPointers: true});
-    ajvErrors(ajv, {keepErrors: true});
   });
 
-  describe('keepErrors: true', function() {
+  describe('keepErrors = true', function() {
+    beforeEach(function() {
+      ajvErrors(ajv, {keepErrors: true});
+    });
+
     describe('errorMessage is a string', function() {
       it('should keep matched errors and mark them with {emUsed: true} property', function() {
         var schema = {
@@ -138,6 +141,58 @@ describe('options', function() {
   });
 
 
+  describe('singleError', function() {
+    describe('= true', function() {
+      it('should generate a single error for all keywords', function() {
+        ajvErrors(ajv, {singleError: true});
+        testSingleErrors('; ');
+      });
+    });
+
+    describe('= separator', function() {
+      it('should generate a single error for all keywords using separator', function() {
+        ajvErrors(ajv, {singleError: '\n'});
+        testSingleErrors('\n');
+      });
+    });
+
+    function testSingleErrors(separator) {
+      var schema = {
+        type: 'number',
+        minimum: 2,
+        maximum: 10,
+        multipleOf: 2,
+        errorMessage: {
+          type: 'should be number',
+          minimum: 'should be >= 2',
+          maximum: 'should be <= 10',
+          multipleOf: 'should be multipleOf 2'
+        }
+      };
+
+      var validate = ajv.compile(schema);
+      assert.strictEqual(validate(4), true);
+      assert.strictEqual(validate(11), false);
+
+      var expectedKeywords = ['maximum', 'multipleOf'];
+      var expectedMessage = expectedKeywords
+                            .map(function (keyword) {
+                              return schema.errorMessage[keyword];
+                            })
+                            .join(separator);
+
+      assertErrors(validate, [
+        {
+          keyword: 'errorMessage',
+          message: expectedMessage,
+          dataPath: '',
+          errors: expectedKeywords
+        }
+      ]);
+    }
+  });
+
+
   function assertErrors(validate, expectedErrors) {
     assert.strictEqual(validate.errors.length, expectedErrors.length);