diff --git a/lib/cov_command.js b/lib/cov_command.js
index 5b2ab8fd..ea2118f6 100644
--- a/lib/cov_command.js
+++ b/lib/cov_command.js
@@ -29,6 +29,9 @@ class CovCommand extends Command {
     yield this.helper.checkDeps();
 
     const covFile = require.resolve('istanbul/lib/cli.js');
+    // resolve istanbul path for coffee
+    /* istanbul ignore next */
+    process.env.istanbul_bin_path = covFile;
     const opt = {
       env: process.env,
     };