diff --git a/modules/programs/bash/default.nix b/modules/programs/bash/default.nix
index 2e27ff9..3abb3e8 100644
--- a/modules/programs/bash/default.nix
+++ b/modules/programs/bash/default.nix
@@ -55,9 +55,6 @@ in
       if [ -n "$__ETC_BASHRC_SOURCED" -o -n "$NOSYSBASHRC" ]; then return; fi
       __ETC_BASHRC_SOURCED=1
 
-      # Don't execute this file when running in a pure nix-shell.
-      if [ "$IN_NIX_SHELL" = "pure" ]; then return; fi
-
       if [ -z "$__NIX_DARWIN_SET_ENVIRONMENT_DONE" ]; then
         . ${config.system.build.setEnvironment}
       fi
diff --git a/modules/programs/zsh/default.nix b/modules/programs/zsh/default.nix
index 7574f8e..bfbfc59 100644
--- a/modules/programs/zsh/default.nix
+++ b/modules/programs/zsh/default.nix
@@ -127,9 +127,6 @@ in
       if [ -n "''${__ETC_ZSHENV_SOURCED-}" ]; then return; fi
       __ETC_ZSHENV_SOURCED=1
 
-      # Don't execute this file when running in a pure nix-shell.
-      if test -n "$IN_NIX_SHELL"; then return; fi
-
       if [ -z "''${__NIX_DARWIN_SET_ENVIRONMENT_DONE-}" ]; then
         . ${config.system.build.setEnvironment}
       fi
diff --git a/tests/programs-zsh.nix b/tests/programs-zsh.nix
index dd5f6e9..9c98c33 100644
--- a/tests/programs-zsh.nix
+++ b/tests/programs-zsh.nix
@@ -22,8 +22,6 @@
 
      echo >&2 "checking setEnvironment in /etc/zshenv"
      fgrep '. ${config.system.build.setEnvironment}' ${config.out}/etc/zshenv
-     echo >&2 "checking nix-shell return /etc/zshenv"
-     grep 'if test -n "$IN_NIX_SHELL"; then return; fi' ${config.out}/etc/zshenv
      echo >&2 "checking zshenv.d in /etc/zshenv"
      grep 'source /etc/zshenv.d/\*.conf' ${config.out}/etc/zshenv