diff --git a/NAMESPACE b/NAMESPACE
index 5c40bf3..fa77c29 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1,8 +1,10 @@
 # Generated by roxygen2: do not edit by hand
 
 S3method(base::as.character,vctrs_rcrd)
+S3method(collapse::fmax,integer64)
 S3method(collapse::fmean,integer64)
 S3method(collapse::fmedian,integer64)
+S3method(collapse::fmin,integer64)
 S3method(collapse::fnobs,integer64)
 S3method(collapse::fnth,integer64)
 S3method(collapse::fsd,integer64)
diff --git a/R/utils.R b/R/utils.R
index 265969d..12691b6 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -141,6 +141,16 @@ funique.POSIXlt <- function(x, sort = FALSE, ...){
   out
 }
 
+# collapse methods for integer64
+
+#' @exportS3Method collapse::fmin
+fmin.integer64 <- function(x, ...){
+  collapse::fmin(cpp_int64_to_double(x), ...)
+}
+#' @exportS3Method collapse::fmax
+fmax.integer64 <- function(x, ...){
+  collapse::fmax(cpp_int64_to_double(x), ...)
+}
 #' @exportS3Method collapse::fmean
 fmean.integer64 <- function(x, ...){
   collapse::fmean(cpp_int64_to_double(x), ...)