During the past decade, field studies to assess the potential impact of agricultural chemicals on aquatic ecosystems have increased in number and sophistication. As the questions addressed in these studies have become more complex, the traditional “farm pond” study has evolved into an elaborate fate and effects study. This paper will examine the increasing complexity of aquatic field studies over the past ten years using as examples studies conducted to support the registration of three pyrethroid insecticides: permethrin, cypermethrin, and bifenthrin. A permethrin study was conducted in a single season (1976) using a minimal regime of residue and biological samplings. The current bifenthrin study has involved extensive biological residue sampling with in situ populations of vertebrate and invertebrate species, on-site bioassays, and community metabolism over a three-year period (1985–1987). The future trends for aquatic field studies will also be discussed, including replicate treatment ponds, management of fish populations, and the use of experimental enclosures.