This document specifies approaches for the determination of plutonium isotopes (238Pu, 239Pu and 240Pu) in urine using alpha spectrometry or inductively coupled plasma mass spectrometry (ICP-MS). It is applicable to the measurement of plutonium isotopes at levels which are appropriate for — workers handling plutonium in planned exposure situations, where detection limits are sufficiently low to be in accordance with dose limits, and — workers, members of the public and emergency responders in emergency exposure situations, where required detection limits can be much higher, and results need to be reported in a short timescale. This document does not provide information on when monitoring is carried out or the interpretation of the results in terms of dose or biological effects.