diff --git a/NEWS.md b/NEWS.md
index 7c2501d..8b8a0a2 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # memoise (development version)
 
+* `omit_args` now also works for default arguments (@mgirlich, #145).
+
 # memoise 2.0.1
 
 # Version 2.0.0.9000
diff --git a/R/memoise.R b/R/memoise.R
index 673be92..96deedc 100644
--- a/R/memoise.R
+++ b/R/memoise.R
@@ -148,13 +148,13 @@ memoise <- memoize <- function(
     # That has not been called
     default_args <- default_args[setdiff(names(default_args), names(called_args))]
 
-    # Ignored specified arguments when hashing
-    called_args[encl$`_omit_args`] <- NULL
-
     # Evaluate all the arguments
     args <- c(lapply(called_args, eval, parent.frame()),
               lapply(default_args, eval, envir = environment()))
 
+    # Ignored specified arguments when hashing
+    args[encl$`_omit_args`] <- NULL
+
     key <- encl$`_hash`(
       c(
         encl$`_f_hash`,
diff --git a/tests/testthat/test-memoise.R b/tests/testthat/test-memoise.R
index bb26a4a..b36032b 100644
--- a/tests/testthat/test-memoise.R
+++ b/tests/testthat/test-memoise.R
@@ -326,6 +326,29 @@ test_that("omit_args respected", {
   res2 <- mem_rnorm(10, mean = +100)
 
   expect_true(identical(res1, res2))
+
+  # Also works for default arguments
+  a <- 0
+  f <- function(x = a) {
+    a <<- a + 1
+    a
+  }
+
+  # everytime `f()` is called its value increases by 1
+  expect_equal(f(), 1)
+  expect_equal(f(), 2)
+
+  # it still increases by one when memoised as the argument `x` changes
+  a <- 0
+  mem_f <- memoise::memoise(f)
+  expect_equal(mem_f(), 1)
+  expect_equal(mem_f(), 2)
+
+  # but `x` can be ignored via `omit_args`
+  a <- 0
+  mem_f2 <- memoise(f, omit_args = "x")
+  expect_equal(mem_f2(), 1)
+  expect_equal(mem_f2(), 1)
 })
 
 context("has_cache")