In this preliminary study, blood plasma samples from 32 insulintreated (ITDM),55 non-insulin-treated (NITDM) diabetic patients, and 30 nondiabetic individuals (C-NDM) (all fasting) from Oxford, England, were analyzed for Ag, Al, As, Ba, Br, Ca, Cd, Co, Cr, Cs, Cu, Fe, Hg, I, Mg, Mn, Mo, Ni, Pb, Rb, Sb, Sc, Se, Sn, V, and Zn. Neutron activation analysis and electrothermal atomic absorption methods were used. Analysis of a "pooled standard" blood plasma for 17 elements showed a good agreement with most coefficients of variation less than 15%, and recoveries of 92-102%. The elemental concentrations for healthy individuals and ITDM each obey an almost normal distribution, while those of NITDM deviate greatly from this. The NITDM group has a marked tendency to increased mean elemental values. Comparison between C-NDM and ITDM shows no significant relationship with relative periodic table position, biological essentiality or toxic behavior-and there is uniformly no increase in variability (as with NITDM). There is no significant difference in plasma chromium levels between the diabetic groups; however, each was significantly higher than the controls; ITDM (S**: probability less than 0.005) and NITDM (S*: probability between 0.05 and 0.01). Those diabetics on insulin treatment were significantly lower in plasma zinc compared with the other two groups.