diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## v0.3.1
+
+ - Fix bug in perfdata rendering wherein scientific notation was used
+   for large/small values.
+
 ## v0.3.0
 
  - Added addPerfData function and ToPerfData typeclass for more convenient
diff --git a/lib/System/Nagios/Plugin/PerfData.hs b/lib/System/Nagios/Plugin/PerfData.hs
--- a/lib/System/Nagios/Plugin/PerfData.hs
+++ b/lib/System/Nagios/Plugin/PerfData.hs
@@ -16,13 +16,14 @@
 import           Data.Int
 import           Data.Nagios.Perfdata.Metric (UOM (..))
 import           Data.Text                   (Text)
+import           Numeric
 
 -- | Value of a performance metric.
 data PerfValue = RealValue Double | IntegralValue Int64
   deriving (Eq, Ord)
 
 instance Show PerfValue where
-    show (RealValue x) = show x
+    show (RealValue x) = showFFloat Nothing x ""
     show (IntegralValue x) = show x
 
 -- | One performance metric. A plugin will output zero or more of these,
diff --git a/nagios-check.cabal b/nagios-check.cabal
--- a/nagios-check.cabal
+++ b/nagios-check.cabal
@@ -1,5 +1,5 @@
 name:                nagios-check
-version:             0.3.0
+version:             0.3.1
 synopsis:            Package for writing monitoring plugins
 description:         Implements Nagios plugin development guidelines
                      within a Haskell framework for writing Nagios