The polarographic behaviour of Aztreonam is studied. In acid media, at pH values lower than 6, in differential pulse polarography a peak is observed at a potential close to − 0.6 volts. The optimum conditions for the polarographic signal are established and the different parameters affecting the electrochemical process are studied. The relationship between peak intensity and the concentration of Aztreonam is linear for concentrations lower than 1.0 − 10−5M, the detection limit being 1.4 × 10−8M It was observed that the presence of 1-arginine does not affect the polarographic signal of Aztreonam to any significant extent.