Hemilepistus reaumuri(Audouin & Savigny 1826) forms a large proportion of the woodlice in the neighbourhood of Benghazi, Libya. Laboratory observations, over a period of 7 days, were made to study the effects of sub-lethal concentrations of the pesticides Lannate and Lebaycid (insecticides), Remiltine (fungicide) and Glyphosate (herbicide). These are in common use in farms around Benghazi. Pesticides had a significant influence on survival rates, body weights and rates of oxygen consumption in both sexes. Survival was adversely affected by exposure to Lebaycid and Glyphosate, and all four pesticides had an adverse influence on body weight. Rates of oxygen consumption of pesticide-treated woodlice showed an increase during the initial exposure. They tended to level off towards the end of the experimental period. The ecological implications of these findings are discussed.