diff --git a/R/sim_pw_surv.R b/R/sim_pw_surv.R
index a9c604fc..6d4b3a69 100644
--- a/R/sim_pw_surv.R
+++ b/R/sim_pw_surv.R
@@ -142,6 +142,13 @@ sim_pw_surv <- function(
       duration = rep(100, 2),
       rate = rep(.001, 2)
     )) {
+  # Enforce consistent treatment names
+  treatments <- unique(c(block, fail_rate$treatment, dropout_rate$treatment))
+  stopifnot(
+    treatments %in% block,
+    treatments %in% fail_rate$treatment,
+    treatments %in% dropout_rate$treatment
+  )
   # Start table by generating stratum and enrollment times
   x <- data.table(stratum = sample(
     x = stratum$stratum,
diff --git a/tests/testthat/test-double_programming_simPWSurv.R b/tests/testthat/test-double_programming_simPWSurv.R
index ef7fa4d6..d8460b62 100644
--- a/tests/testthat/test-double_programming_simPWSurv.R
+++ b/tests/testthat/test-double_programming_simPWSurv.R
@@ -127,3 +127,30 @@ zevent <- dplyr::bind_rows(rate00, rate01, rate10, rate11)
 testthat::test_that("The actual number of events changes by changing total sample size", {
   expect_false(unique(xevent$event == zevent$event))
 })
+
+testthat::test_that("sim_pw_surv() fails early with mismatched treatment names", {
+  block <- c(rep("x", 2), rep("y", 2))
+  fail_rate <- data.frame(
+    stratum = rep("All", 4),
+    period = rep(1:2, 2),
+    treatment = c(rep("x", 2), rep("y", 2)),
+    duration = rep(c(3, 1), 2),
+    rate = log(2) / c(9, 9, 9, 18)
+  )
+  dropout_rate <- data.frame(
+    stratum = rep("All", 2),
+    period = rep(1, 2),
+    treatment = c("x", "y"),
+    duration = rep(100, 2),
+    rate = rep(0.001, 2)
+  )
+
+  expect_error(sim_pw_surv(block = block))
+  expect_error(sim_pw_surv(fail_rate = fail_rate))
+  expect_error(sim_pw_surv(dropout_rate = dropout_rate))
+  # works as long as treatment names are consistent
+  expect_silent(
+    xy <- sim_pw_surv(block = block, fail_rate = fail_rate, dropout_rate = dropout_rate)
+  )
+  expect_identical(sort(unique(xy$treatment)), c("x", "y"))
+})