diff --git a/include/particle_generator.hh b/include/particle_generator.hh
index 56c69f4..956ed28 100644
--- a/include/particle_generator.hh
+++ b/include/particle_generator.hh
@@ -37,7 +37,7 @@ const std::vector<vec3<real_t>> second_lattice_shift =
 };
 
 template<typename field_t>
-void initialize_lattice( container& particles, lattice lattice_type, const bool b64reals, const bool b64ids, const field_t& field ){
+void initialize_lattice( container& particles, lattice lattice_type, const bool b64reals, const bool b64ids, const size_t IDoffset, const field_t& field ){
     // number of modes present in the field
     const size_t num_p_in_load = field.local_size();
     // unless SC lattice is used, particle number is a multiple of the number of modes (=num_p_in_load):
@@ -50,9 +50,9 @@ void initialize_lattice( container& particles, lattice lattice_type, const bool
             for( size_t k=0; k<field.size(2); ++k,++ipcount){
                 for( size_t iload=0; iload<overload; ++iload ){
                     if( b64ids ){
-                        particles.set_id64( ipcount+iload*num_p_in_load, overload*field.get_cell_idx_1d(i,j,k)+iload );
+                        particles.set_id64( ipcount+iload*num_p_in_load, IDoffset + overload*field.get_cell_idx_1d(i,j,k)+iload );
                     }else{
-                        particles.set_id32( ipcount+iload*num_p_in_load, overload*field.get_cell_idx_1d(i,j,k)+iload );
+                        particles.set_id32( ipcount+iload*num_p_in_load, IDoffset + overload*field.get_cell_idx_1d(i,j,k)+iload );
                     }
                 }
             }
diff --git a/src/ic_generator.cc b/src/ic_generator.cc
index a9d9670..ce86444 100644
--- a/src/ic_generator.cc
+++ b/src/ic_generator.cc
@@ -540,11 +540,14 @@ int Run( ConfigFile& the_config )
                 bool shifted_lattice = (this_species == cosmo_species::baryon &&
                                         the_output_plugin->write_species_as(this_species) == output_type::particles) ? true : false;
 
+                // somewhat arbitrarily, start baryon particle IDs from 2**31 if we have 32bit and from 2**56 if we have 64 bits
+                size_t IDoffset = (this_species == cosmo_species::baryon)? ((the_output_plugin->has_64bit_ids())? 1ul<<56 : 1ul<<31): 0 ;
+
                 // if output plugin wants particles, then we need to store them, along with their IDs
                 if( the_output_plugin->write_species_as( this_species ) == output_type::particles )
                 {
                     // allocate particle structure and generate particle IDs
-                    particle::initialize_lattice( particles, lattice_type, the_output_plugin->has_64bit_reals(), the_output_plugin->has_64bit_ids(), tmp );
+                    particle::initialize_lattice( particles, lattice_type, the_output_plugin->has_64bit_reals(), the_output_plugin->has_64bit_ids(), IDoffset, tmp );
                 }
             
                 // write out positions