The effect of isofenphos (Oftanol) on nontarget invertebrates in turfgrass was determined by comparing population dynamics of eight taxa sampled from treated versus untreated halves of home lawns. Lawns were treated in late summer 1980 or spring 1981. Populations of predacious Acari, Collembola, Diplopoda, Diplura, and Staphylinidae were reduced in treated areas. Higher populations of oribatid Acari and Enchytraeidae were found in treated areas. The time required for recovery ranged from several weeks to 8–10 mo depending on the taxa; edaphic and predacious groups were affected the longest.