diff --git a/cli/tools/registry/pm.rs b/cli/tools/registry/pm.rs
index f56774e8eb5675..5dc04262028297 100644
--- a/cli/tools/registry/pm.rs
+++ b/cli/tools/registry/pm.rs
@@ -130,8 +130,10 @@ impl NpmConfig {
   fn add(&mut self, selected: SelectedPackage, dev: bool) {
     let (name, version) = package_json_dependency_entry(selected);
     if dev {
+      self.dependencies.swap_remove(&name);
       self.dev_dependencies.insert(name, version);
     } else {
+      self.dev_dependencies.swap_remove(&name);
       self.dependencies.insert(name, version);
     }
   }
diff --git a/tests/specs/install/install_add_dep_existing/__test__.jsonc b/tests/specs/install/install_add_dep_existing/__test__.jsonc
new file mode 100644
index 00000000000000..74c509a57d9f0d
--- /dev/null
+++ b/tests/specs/install/install_add_dep_existing/__test__.jsonc
@@ -0,0 +1,16 @@
+{
+  "tempDir": true,
+  "steps": [
+    {
+      "args": "install npm:@denotest/esm-basic",
+      "output": "install.out"
+    },
+    {
+      "args": [
+        "eval",
+        "console.log(Deno.readTextFileSync('package.json').trim())"
+      ],
+      "output": "package.json.out"
+    }
+  ]
+}
diff --git a/tests/specs/install/install_add_dep_existing/install.out b/tests/specs/install/install_add_dep_existing/install.out
new file mode 100644
index 00000000000000..42161f3ae1d01c
--- /dev/null
+++ b/tests/specs/install/install_add_dep_existing/install.out
@@ -0,0 +1,4 @@
+Add npm:@denotest/esm-basic@1.0.0
+Download http://localhost:4260/@denotest/esm-basic
+Download http://localhost:4260/@denotest/esm-basic/1.0.0.tgz
+Initialize @denotest/esm-basic@1.0.0
diff --git a/tests/specs/install/install_add_dep_existing/package.json b/tests/specs/install/install_add_dep_existing/package.json
new file mode 100644
index 00000000000000..d5ca56e00478be
--- /dev/null
+++ b/tests/specs/install/install_add_dep_existing/package.json
@@ -0,0 +1,3 @@
+{
+  "devDependencies": { "@denotest/esm-basic": "^1.0.0" }
+}
diff --git a/tests/specs/install/install_add_dep_existing/package.json.out b/tests/specs/install/install_add_dep_existing/package.json.out
new file mode 100644
index 00000000000000..613d9863605e42
--- /dev/null
+++ b/tests/specs/install/install_add_dep_existing/package.json.out
@@ -0,0 +1,5 @@
+{
+  "dependencies": {
+    "@denotest/esm-basic": "^1.0.0"
+  }
+}
diff --git a/tests/specs/install/install_add_dev_existing/__test__.jsonc b/tests/specs/install/install_add_dev_existing/__test__.jsonc
new file mode 100644
index 00000000000000..e4e2f8a31c3c87
--- /dev/null
+++ b/tests/specs/install/install_add_dev_existing/__test__.jsonc
@@ -0,0 +1,16 @@
+{
+  "tempDir": true,
+  "steps": [
+    {
+      "args": "install --dev npm:@denotest/esm-basic",
+      "output": "install.out"
+    },
+    {
+      "args": [
+        "eval",
+        "console.log(Deno.readTextFileSync('package.json').trim())"
+      ],
+      "output": "package.json.out"
+    }
+  ]
+}
diff --git a/tests/specs/install/install_add_dev_existing/install.out b/tests/specs/install/install_add_dev_existing/install.out
new file mode 100644
index 00000000000000..42161f3ae1d01c
--- /dev/null
+++ b/tests/specs/install/install_add_dev_existing/install.out
@@ -0,0 +1,4 @@
+Add npm:@denotest/esm-basic@1.0.0
+Download http://localhost:4260/@denotest/esm-basic
+Download http://localhost:4260/@denotest/esm-basic/1.0.0.tgz
+Initialize @denotest/esm-basic@1.0.0
diff --git a/tests/specs/install/install_add_dev_existing/package.json b/tests/specs/install/install_add_dev_existing/package.json
new file mode 100644
index 00000000000000..ad8518e791a975
--- /dev/null
+++ b/tests/specs/install/install_add_dev_existing/package.json
@@ -0,0 +1,3 @@
+{
+  "dependencies": { "@denotest/esm-basic": "^1.0.0" }
+}
diff --git a/tests/specs/install/install_add_dev_existing/package.json.out b/tests/specs/install/install_add_dev_existing/package.json.out
new file mode 100644
index 00000000000000..866724397f1903
--- /dev/null
+++ b/tests/specs/install/install_add_dev_existing/package.json.out
@@ -0,0 +1,5 @@
+{
+  "devDependencies": {
+    "@denotest/esm-basic": "^1.0.0"
+  }
+}