diff --git a/inst/include/monty/random/multinomial.hpp b/inst/include/monty/random/multinomial.hpp
index 6d3770b6..f64b8f80 100644
--- a/inst/include/monty/random/multinomial.hpp
+++ b/inst/include/monty/random/multinomial.hpp
@@ -53,7 +53,7 @@ namespace random {
 template <typename real_type, typename rng_state_type,
           typename T, typename U>
 __host__ __device__
-void multinomial(rng_state_type& rng_state, int size, const T& prob,
+void multinomial(rng_state_type& rng_state, real_type size, const T& prob,
                  int prob_len, U ret) {
   real_type p_tot = 0;
   for (int i = 0; i < prob_len; ++i) {
diff --git a/tests/testthat/test-rng.R b/tests/testthat/test-rng.R
index 43d170cf..d2365cb7 100644
--- a/tests/testthat/test-rng.R
+++ b/tests/testthat/test-rng.R
@@ -632,6 +632,15 @@ test_that("can validate multinomial inputs", {
 })
 
 
+test_that("deterministic multinomial returns expectation", {
+  r <- monty_rng_create(seed = 1, deterministic = TRUE)
+  p <- runif(10)
+  p <- p / sum(p)
+  res <- monty_random_multinomial(100, p, r)
+  expect_equal(res, 100 * p)
+})
+
+
 test_that("deterministic rbinom returns mean", {
   m <- 10
   n <- as.numeric(sample(10, m, replace = TRUE))