diff --git a/homeassistant/components/modbus/__init__.py b/homeassistant/components/modbus/__init__.py
index 0ceb1a2523fc3c..1151a5f1f013db 100644
--- a/homeassistant/components/modbus/__init__.py
+++ b/homeassistant/components/modbus/__init__.py
@@ -342,8 +342,8 @@
             vol.Optional(CONF_UNIT_OF_MEASUREMENT): cv.string,
             vol.Exclusive(CONF_VIRTUAL_COUNT, "vir_sen_count"): cv.positive_int,
             vol.Exclusive(CONF_SLAVE_COUNT, "vir_sen_count"): cv.positive_int,
-            vol.Optional(CONF_MIN_VALUE): cv.positive_float,
-            vol.Optional(CONF_MAX_VALUE): cv.positive_float,
+            vol.Optional(CONF_MIN_VALUE): vol.Coerce(float),
+            vol.Optional(CONF_MAX_VALUE): vol.Coerce(float),
             vol.Optional(CONF_NAN_VALUE): nan_validator,
             vol.Optional(CONF_ZERO_SUPPRESS): cv.positive_float,
         }
diff --git a/tests/components/modbus/test_sensor.py b/tests/components/modbus/test_sensor.py
index 5ca38873c423c7..aa8b15585dc887 100644
--- a/tests/components/modbus/test_sensor.py
+++ b/tests/components/modbus/test_sensor.py
@@ -185,6 +185,28 @@
                 }
             ]
         },
+        {
+            CONF_SENSORS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 51,
+                    CONF_DATA_TYPE: DataType.INT16,
+                    CONF_MIN_VALUE: 1,
+                    CONF_MAX_VALUE: 3,
+                }
+            ]
+        },
+        {
+            CONF_SENSORS: [
+                {
+                    CONF_NAME: TEST_ENTITY_NAME,
+                    CONF_ADDRESS: 51,
+                    CONF_DATA_TYPE: DataType.INT16,
+                    CONF_MIN_VALUE: -3,
+                    CONF_MAX_VALUE: -1,
+                }
+            ]
+        },
     ],
 )
 async def test_config_sensor(hass: HomeAssistant, mock_modbus) -> None: