Five platinum pyridin-2-ylcarboxaldimine complexes of the type cis-[PtCl2(2-C5H4NCH=NR)] (R = CH2CH2OH (1); R = N(CH2CH2)2O (2); R = C6H5 (3); R = 1-C10H7 (4); R = (CH2)8CH=CH(CH2)7CH3 (5)) were prepared and their in vitro reactivity towards a 20-base pair (single- and double-stranded) DNA determined using nuclease digest studies and RP-HPLC. Variation of the imine functionality allowed for the design of compounds with different physical and chemical properties. Complexes 1 and 3 showed binding to both single- and double-stranded DNA comparable to that of cisplatin (cis-[PtCl2(NH3)2]). Crystals of 1 were monoclinic, space group P2(1)/n, a = 9.6612 (15), b = 12.9678 (19), c = 9.7004(13) Å, β = 117.73(3)°, Z = 4.Key words: platinum, pyridin-2-ylcarboxaldimines, DNA binding studies.