diff --git a/src/global.f90 b/src/global.f90
index e7757a0eb..23fd8f2ea 100644
--- a/src/global.f90
+++ b/src/global.f90
@@ -20,7 +20,6 @@ module global
   type(Lattice),  allocatable, target :: lattices(:)
   type(Surface),  allocatable, target :: surfaces(:)
   type(Material), allocatable, target :: materials(:)
-  type(Isotope),  allocatable, target :: isotopes(:)
   type(xsData),   allocatable, target :: xsdatas(:)
   type(Tally),    allocatable, target :: tallies(:)
   type(Tally),    allocatable, target :: tallies_global(:)
diff --git a/src/types.f90 b/src/types.f90
index 522ef7785..4b9fc4bc3 100644
--- a/src/types.f90
+++ b/src/types.f90
@@ -143,19 +143,6 @@ module types
      type(TallyScore), allocatable :: score(:,:,:)
   end type Tally
 
-!===============================================================================
-! ISOTOPE describes an isotope, e.g. U-235, within a material. Note that two
-! separate variables must be used for the same isotope in two different
-! materials since they will generally have different densities
-!===============================================================================
-
-  type Isotope
-     integer :: uid     ! unique identifier
-     integer :: zaid    ! ZAID, e.g. 92235
-     character(3) :: xs ! cross section identifier, e.g. 70c
-     real(8) :: density ! density in atom/b-cm
-  end type Isotope
-
 !===============================================================================
 ! MATERIAL describes a material by its constituent isotopes
 !===============================================================================