Abstract: The determination of mass percentage of oxygen in tantalum and tungsten coats by pulse meltinginfrared absorption spectrometry is described in this paper with emphasis on the influence of the electric power for analysis, fusing agent, crucible type, reagents and crucible blanks, and sample size on the determination results. Based on these experimental results a procedure for determination of trace oxygen in these coats is established. The procedure is examined with tantalum and tungsten coat samples and two reference materials. The results show that the relative standard deviations are 2.94% and 6.01%(n=6) for tantalum and tungsten coats and the recoveries are in the range of 93%-108% for the former and 92%-108% for the latter.