The concentrations of titanium and vanadium in biological material, human blood serum, were determined by neutron activation analysis, using a prior coprecipitation with Pb/PDC/2 as well as Bi/PDC/3. Titanium and vanadium were quantitatively determined by measuring the gamma ray photopeaks of the short-lived radionuclides51Ti /5.8 min/ and52V /3.75 min/, respectively. The concentrations ranged from 105.7 to 131.9 ng ml–1 /Ti/ and from 1.30 to 6.05 ng ml–1 /V/. The detection limits for titanium and vanadium under the present experimental conditions were found to be 70 and 0.7 ng for 1 ml of blood serum sample, respectively.