This study describes the uptake and elimination of 2,3,4,5-tetrachloroaniline, 2,3,5,6-tetrachloroaniline, pentachloroaniline, and 1,2,3,5-tetrachlorobenzene in guppy, Poecilia reticulaza. The experimentally determined bioconcentration factors of the chlorinated anilines in guppy are much lower than can be expected based on previously published linear relationships between log BCF and log K(OW) for chlorobenzenes. In contrast to the mono-phasic elimination of 1,2,3,5-tetrachlorobenzene, the elimination of the chlorinated anilines is best described by a bi-exponential equation. The initial fast elimination of the chloroanilines is the cause for the relatively low BCF values of 2,3,5,6-tetrachloroaniline and pentachloroaniline. The lower BCF value of 2.3,4,5-tetrachloroaniline may be caused by a lower uptake rate in combination with an initial fast elimination.