diff --git a/Project.toml b/Project.toml
index fc233e7..52e1677 100644
--- a/Project.toml
+++ b/Project.toml
@@ -5,6 +5,7 @@ version = "1.0.0-DEV"
 
 [deps]
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
+Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 
 [compat]
diff --git a/src/AwkwardArray.jl b/src/AwkwardArray.jl
index 04a3bb0..68cddad 100644
--- a/src/AwkwardArray.jl
+++ b/src/AwkwardArray.jl
@@ -1,6 +1,7 @@
 module AwkwardArray
 
 import JSON
+import Dates
 import Tables
 
 ### Index ################################################################
@@ -274,10 +275,10 @@ function _to_buffers!(
         primitive = "complex64"
     elseif ITEM == Complex{Float64}
         primitive = "complex128"
-        # elseif ITEM <: Dates.DateTime     # FIXME
-        #     primitive = "datetime64"
-        # elseif ITEM <: Dates.TimePeriod   # FIXME
-        #     primitive = "timedelta64"
+    elseif ITEM <: DateTime
+        primitive = "datetime64"
+    elseif ITEM <: TimePeriod
+        primitive = "timedelta64"
     else
         error(
             "PrimitiveArray has an ITEM type that can't be serialized in the to_buffers protocol: $ITEM",
@@ -3117,10 +3118,10 @@ function from_buffers(
             data = reinterpret(Complex{Float32}, buffer)
         elseif primitive == "complex128"
             data = reinterpret(Complex{Float64}, buffer)
-            # elseif primitive == "datetime64"
-            #     FIXME: Dates.DateTime
-            # elseif primitive == "timedelta64"
-            #     FIXME: Dates.TimePeriod
+        elseif primitive == "datetime64"
+            data = reinterpret(DateTime, buffer)
+        elseif primitive == "timedelta64"
+            data = reinterpret(TimePeriod, buffer)
         else
             error(
                 "unrecognized \"primitive\": $(repr(primitive)) in \"class\": \"$class\" node",