Abstract.Ectoparasite records are presented for four species of commensal murid rodents (Rattus rattus palelaeMiller&Hollister,R.argentiventer(Robinson&Kloss),R.exulans(Peale) andMus musculus castaneusWaterhouse) in Sulawesi Utara, with particular reference to the potential for these arthropods to bite and transmit pathogens to humans. The flea,Xenopsylla cheopis(Rothschild), was most common onR.r.palelaeand is capable of transmitting plague and other pathogens to humans although no current foci for these diseases are known in Sulawesi.Hoplopleura pacificaEwing andPolyplax spinulosa(Burmeister) sucking lice parasitized all threeRattusspecies althoughH.pacificawas mainly associated withR.exulansandP.spinulosawithR.r.palelae.These lice do not bite humans but may be intramurid vectors of murine typhus and other zoonoses. The mitesLaelaps echidninaBerlese andL.nuttalliHirst were both collected; the latter was recorded from all four murid species, mainlyR.exulans.The miteOrnithonyssus bacotiHirst was rare. Only one chigger mite,Walchiella oudemansi(Walch), was retrieved from murids (fromR.exulans)and a singleLeptotrombidium deliense(Walch) chigger was taken from a human subject. AlthoughL.delienseis a significant vector of scrub typhus, a disease known from Sulawesi, theL.deliense– R.argentiventerrelationship frequently noted in the ecology of this rickettsial disease, was not evident in this survey. Other ectoparasites collected from murids were the ticks,Ixodes granulatusSupino (first record for Sulawesi),Haemaphysalissp. andDermacentorsp., the mitesMyocoptes musculinus(Koch) andListrophoroides cucullatus(Trouessart), acarids and a uropodid. Additional ectoparasites noted on humans were the tickAmblyoma babirussae(Schulze), the scabies miteSarcoptes scabieiL. and the head lousePediculus humanus capitisDe Gee