Three wild-caught Sri Lankan and two captive-bred slender lorises (Loris tardigradus) in Adelaide Zoo, South Australia, were karyotyped from leucocyte cultures. The founder male and one of the founder females were of the grey subspecies L. tardigradus grandis, of which L. tardigradus nordicus is probably a synonym. The other founder female was a small red-brown L. tardigradus tardigradus. All three wild-caught individuals were karyotypically distinct from each other and their offspring showed the expected heterozygosity. The L. tardigradus tardigradus karyotype was no more distinct from the grey subspecies karyotypes than they were from each other. On present evidence, Indian and Sri Lankan lorises appear to be chromosomally distinct.