diff --git a/lib/spack/spack/cmd/activate.py b/lib/spack/spack/cmd/activate.py
index 27f0fc96517..65c0d8d0bef 100644
--- a/lib/spack/spack/cmd/activate.py
+++ b/lib/spack/spack/cmd/activate.py
@@ -26,6 +26,10 @@ def setup_parser(subparser):
 
 
 def activate(parser, args):
+
+    tty.warn("spack activate is deprecated in favor of "
+             "environments and will be removed in v0.19.0")
+
     specs = spack.cmd.parse_specs(args.spec)
     if len(specs) != 1:
         tty.die("activate requires one spec.  %d given." % len(specs))
diff --git a/lib/spack/spack/cmd/deactivate.py b/lib/spack/spack/cmd/deactivate.py
index df3c13fdea5..3d5b5494001 100644
--- a/lib/spack/spack/cmd/deactivate.py
+++ b/lib/spack/spack/cmd/deactivate.py
@@ -32,6 +32,10 @@ def setup_parser(subparser):
 
 
 def deactivate(parser, args):
+
+    tty.warn("spack deactivate is deprecated in favor of "
+             "environments and will be removed in v0.19.0")
+
     specs = spack.cmd.parse_specs(args.spec)
     if len(specs) != 1:
         tty.die("deactivate requires one spec.  %d given." % len(specs))