diff --git a/src/main/scala/scoverage/ScoverageSbtPlugin.scala b/src/main/scala/scoverage/ScoverageSbtPlugin.scala
index 195de89c..ec9a02d5 100644
--- a/src/main/scala/scoverage/ScoverageSbtPlugin.scala
+++ b/src/main/scala/scoverage/ScoverageSbtPlugin.scala
@@ -85,8 +85,14 @@ class ScoverageSbtPlugin extends sbt.Plugin {
                 s"-Xplugin:${classpath.getAbsolutePath}",
                 s"-P:scoverage:dataDir:${crossTarget.value.getAbsolutePath}/scoverage-data"
               ) ++
-                Option(excludedPackages.value).map(v => s"-P:scoverage:excludedPackages:$v") ++
-                Option(scoverageExcludedFiles.value).map(v => s"-P:scoverage:excludedFiles:$v")
+                Option(excludedPackages.value.trim).map{
+                  case "" => ""
+                  case v => s"-P:scoverage:excludedPackages:$v"
+                } ++
+                Option(scoverageExcludedFiles.value.trim).map{
+                  case "" => ""
+                  case v => s"-P:scoverage:excludedFiles:$v"
+                }
           }
         },
 
@@ -436,4 +442,4 @@ class ScoverageSbtPlugin extends sbt.Plugin {
 //  //        test in ScoverageCompile <<= (test in ScoverageTest)
 //  //      )
 //
-//}
\ No newline at end of file
+//}