Under laboratory conditiuons, Tetrastichus sokolowskii attacks Plutella xylostlla larvae of all ages. Development time took from 13 to 19 days The number of adult parasitoids that emerged per pupa was 8.6 +- 0.2, of which 17.3 percent +- 1.2 percent were males. Males were smaller (1.11 +-0.04 mm) than females (1.38 +- 0.04 mm). About 62.7 +- 16.9 offspring could be produced per females and 48 percent of the eggs were laid on th 1st day. Both sexes lived longer when fed on suga or honey solution. When fed honey, the longevity of males and females were 4.8 +- 0.7 and 11.1 +-1.1 respectively. Despite multiple oviposition attacks, there was no significant difference in the number of offspring produced.