The reaction between hydroxylamine and nitric acid in the presence of pertechnetate ions has been studied. Sulphamic acid has been used to remove any nitrous acid formed during the course of the reaction which would otherwise dominate the rate of oxidation. The reaction was shown to have an induction period and then accelerate. Although the reaction mechanism could not be determined, the rate of reaction could be conveniently described by:-<¿[NH 3 OH + ]/df = ¿,[NH 3 OH + ] + fe[NH 3 OH + ]([NH 3 OH + ] 0 -[NH 3 OH + ]')[Tc(VII)][HNO í ] 3 .The rate constants for the two routes of this reaction were found to be ki -(2.8±0.4)X IO -4 min -1 and k 2 = 2.7±0.3 l 5 mol" 5 min -' at 80°C and an ionic strength of 2. The activation energy for the accelerated or autocatalytic reaction route (E 2 ) was determined to be 60±3 kJ mol -1 . k¡ however varied insignificantly with temperature with E, approximately equal to 15±4kJ mol" 1 .