The present experiment was aimed to verify if Cr-EDTA and Co-EDTA are useful as tracers of the glucose distribution volume (GDV) in ewes. Ewes (n equal to 3) fitted with indwelling jugular cannulas and urinary catheters were injected with a single bolus of L-3-glucose, known to be an excellent tracer of GDV, and doses of Cr- and Co-EDTA. The curves of plasma clearance from tracers, and of urine excretion of tracers were analysed. No difference was found in the rate of plasma clearance from L-3H-glucose, compared with the chelates, and between the doses and asymptotic values calculated by exponential analysis of plasma clearance and urinary excretion. However, GDV, measured by using L-3H-glucose as tracer, tended to be greater (p less than 0.12) than measured by using the EDTA-chelates as tracers. Crand Co-EDTA have potential to be useful as tracers of GDV, but additional work with greater numbers of sheep should be carried out before the method is routinely used.