1 files changed, 4 insertions, 0 deletions
diff --git a/lib/csv.rb b/lib/csv.rb
index cd59d8caeb..595586a541 100644
--- a/lib/csv.rb
+++ b/lib/csv.rb
@@ -1484,6 +1484,10 @@ class CSV
   # so be sure to set what you want here.
   #
   def initialize(data, options = Hash.new)
+    if data.nil?
+      raise ArgumentError.new("Cannot parse nil as CSV")
+    end
+
     # build the options for this read/write
     options = DEFAULT_OPTIONS.merge(options)