A population of male bluegill (Lepomis macrochirus) x female green sunfish (Lepomis cyanellus) F1 hybrids was established by parental stocking in a southern Illinois farm pond containing male redear sunfish (Lepomis microlophus) x female green sunfish F1 hybrids and largemouth bass (Micropterus salmoides). In 1967, male redear sunfish and female green sunfish parentals, along with fingerling bass, were stocked into a new farm pond. Nine years later in 1976, male bluegill and female green sunfish were stocked into the same pond. At the time of sampling in the fall of 1978, bluegill x green sunfish F1 hybrids weighed an average of 3 g at annulus I, 24 g at annulus II, and 171 g at annulus III. Growth rates among the three year classes varied widely. The best growth was exhibited by the 1976 year class of bluegill x green sunfish F1 hybrids. Redear x green sunfish F1 hybrids sampled in 1969 weighed an average of 32 g at annulus I, 118 g at annulus II, and 217 g at annulus III. Both F1 hybrid sunfish crosses produced fish that reached the theoretical minimum harvestable size of 110 g at annulus III.