diff --git a/api/src/main/java/org/eclipse/microprofile/metrics/Timer.java b/api/src/main/java/org/eclipse/microprofile/metrics/Timer.java
index d2248a10..fcbd1116 100644
--- a/api/src/main/java/org/eclipse/microprofile/metrics/Timer.java
+++ b/api/src/main/java/org/eclipse/microprofile/metrics/Timer.java
@@ -28,8 +28,6 @@
 
 /**
  * A timer metric which aggregates timing durations and provides duration statistics
- *
- * The timer measures duration in seconds.
  */
 public interface Timer extends Metric, Sampling {
     /**
diff --git a/api/src/main/java/org/eclipse/microprofile/metrics/annotation/Timed.java b/api/src/main/java/org/eclipse/microprofile/metrics/annotation/Timed.java
index 24933ac6..c4ac9ebc 100644
--- a/api/src/main/java/org/eclipse/microprofile/metrics/annotation/Timed.java
+++ b/api/src/main/java/org/eclipse/microprofile/metrics/annotation/Timed.java
@@ -121,7 +121,7 @@
     /**
      * The unit of the timer.
      * 
-     * @return The unit of the timer. By default, the value is {@link MetricUnits#SECONDS}.
+     * @return The unit of the timer. By default, the value is {@link MetricUnits#NANOSECONDS}.
      *
      * @see org.eclipse.microprofile.metrics.Metadata
      * @see org.eclipse.microprofile.metrics.MetricUnits
diff --git a/spec/src/main/asciidoc/app-programming-model.adoc b/spec/src/main/asciidoc/app-programming-model.adoc
index c977781a..a747a2bf 100644
--- a/spec/src/main/asciidoc/app-programming-model.adoc
+++ b/spec/src/main/asciidoc/app-programming-model.adoc
@@ -99,11 +99,11 @@ The following Annotations exist, see below for common fields:
 |@Counted | M, C, T | Denotes a counter, which counts the invocations of the annotated object. | MetricUnits.NONE
 |@Gauge   | M | Denotes a gauge, which samples the value of the annotated object.  | _no default_, must be supplied by the user
 |@Metric  | F, P | An annotation that contains the metadata information when requesting a metric to be injected. | MetricUnits.NONE
-|@Timed   | M, C, T | Denotes a timer, which tracks duration of the annotated object. | MetricUnits.SECONDS
+|@Timed   | M, C, T | Denotes a timer, which tracks duration of the annotated object. | MetricUnits.NANOSECONDS^1^
 |===
-(C=Constructor, F=Field, M=Method, P=Parameter, T=Type)
-
+(C=Constructor, F=Field, M=Method, P=Parameter, T=Type)  
 
+^1^ Prometheus output will always display timer values in _seconds_. When using the `Timer` API to retrieve the `Snapshot`, the values returned from the `Snapshot` will be in nanoseconds. 
 [cols="1,3,2"]
 |===
 |Annotation | Description | Default