diff --git a/build.sh b/build.sh
index d360b8ab609bf364739c19f9745a1c022773ad0e..231b9cab35100c05c4883ce921d2384d66495b05 100644
--- a/build.sh
+++ b/build.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-export FSLDIR=$CONDA_PREFIX
+export FSLDIR=$PREFIX
 export FSLDEVDIR=$PREFIX
 
 . $FSLDIR/etc/fslconf/fsl.sh