diff --git a/pkgs/build-support/rust/import-cargo-lock.nix b/pkgs/build-support/rust/import-cargo-lock.nix
index e3fe57ef06da..3db3f0e5e1f0 100644
--- a/pkgs/build-support/rust/import-cargo-lock.nix
+++ b/pkgs/build-support/rust/import-cargo-lock.nix
@@ -12,6 +12,8 @@
 
   # Additional registries to pull sources from
   #   { "https://<registry index URL>" = "https://<registry download URL>"; }
+  #   or if the registry is using the new sparse protocol
+  #   { "sparse+https://<registry download URL>" = "https://<registry download URL>"; }
   # where:
   # - "index URL" is the "index" value of the configuration entry for that registry
   #   https://doc.rust-lang.org/cargo/reference/registries.html#using-an-alternate-registry
@@ -117,7 +119,8 @@ let
       gitParts = parseGit pkg.source;
       registryIndexUrl = lib.removePrefix "registry+" pkg.source;
     in
-      if lib.hasPrefix "registry+" pkg.source && builtins.hasAttr registryIndexUrl registries then
+      if (lib.hasPrefix "registry+" pkg.source || lib.hasPrefix "sparse+" pkg.source)
+        && builtins.hasAttr registryIndexUrl registries then
       let
         crateTarball = fetchCrate pkg registries.${registryIndexUrl};
       in runCommand "${pkg.name}-${pkg.version}" {} ''
diff --git a/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/.cargo/config.toml b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/.cargo/config.toml
new file mode 100644
index 000000000000..be8d304fa79d
--- /dev/null
+++ b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/.cargo/config.toml
@@ -0,0 +1,5 @@
+[registries.sparse-crates-io]
+index = "sparse+https://index.crates.io/"
+
+[registries.crates-io]
+protocol = "git"
diff --git a/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/Cargo.lock b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/Cargo.lock
new file mode 100644
index 000000000000..104557e66a7b
--- /dev/null
+++ b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/Cargo.lock
@@ -0,0 +1,75 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "basic-sparse"
+version = "0.1.0"
+dependencies = [
+ "rand",
+]
+
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "sparse+https://index.crates.io/"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "getrandom"
+version = "0.2.14"
+source = "sparse+https://index.crates.io/"
+checksum = "94b22e06ecb0110981051723910cbf0b5f5e09a2062dd7663334ee79a9d1286c"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
+[[package]]
+name = "libc"
+version = "0.2.153"
+source = "sparse+https://index.crates.io/"
+checksum = "9c198f91728a82281a64e1f4f9eeb25d82cb32a5de251c6bd1b5154d63a8e7bd"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.17"
+source = "sparse+https://index.crates.io/"
+checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
+
+[[package]]
+name = "rand"
+version = "0.8.5"
+source = "sparse+https://index.crates.io/"
+checksum = "34af8d1a0e25924bc5b7c43c079c942339d8f0a8b57c39049bef581b46327404"
+dependencies = [
+ "libc",
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.3.1"
+source = "sparse+https://index.crates.io/"
+checksum = "e6c10a63a0fa32252be49d21e7709d4d4baf8d231c2dbce1eaa8141b9b127d88"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.6.4"
+source = "sparse+https://index.crates.io/"
+checksum = "ec0be4795e2f6a28069bec0b5ff3e2ac9bafc99e6a9a7dc3547996c5c816922c"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "wasi"
+version = "0.11.0+wasi-snapshot-preview1"
+source = "sparse+https://index.crates.io/"
+checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
diff --git a/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/Cargo.toml b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/Cargo.toml
new file mode 100644
index 000000000000..1e62743eff18
--- /dev/null
+++ b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "basic-sparse"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+rand = { version = "0.8", registry = "sparse-crates-io" }
diff --git a/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/default.nix b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/default.nix
new file mode 100644
index 000000000000..7a87a69e5dac
--- /dev/null
+++ b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/default.nix
@@ -0,0 +1,33 @@
+{ lib, rustPlatform }:
+let
+  fs = lib.fileset;
+in
+rustPlatform.buildRustPackage {
+  pname = "basic-sparse";
+  version = "0.1.0";
+
+  src = fs.toSource {
+    root = ./.;
+    fileset = fs.unions [
+      ./.cargo/config.toml
+      ./Cargo.toml
+      ./Cargo.lock
+      ./src
+    ];
+  };
+
+  cargoLock = {
+    lockFile = ./Cargo.lock;
+    extraRegistries = {
+        "sparse+https://index.crates.io/" = "https://static.crates.io/crates";
+    };
+  };
+
+  doInstallCheck = true;
+  postConfigure = ''
+    cargo metadata --offline
+  '';
+  installCheckPhase = ''
+    $out/bin/basic-sparse
+  '';
+}
diff --git a/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/src/main.rs b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/src/main.rs
new file mode 100644
index 000000000000..50b4ed799e43
--- /dev/null
+++ b/pkgs/build-support/rust/test/import-cargo-lock/basic-sparse/src/main.rs
@@ -0,0 +1,9 @@
+use rand::Rng;
+
+fn main() {
+    let mut rng = rand::thread_rng();
+
+    // Always draw zero :).
+    let roll: u8 = rng.gen_range(0..1);
+    assert_eq!(roll, 0);
+}