The model is estimated using data from England and Wales where fines are levied in 48 percent of all indictable offenses, more than 90 percent of nonindictable offenses, and 98 percent of motoring offenses. This paper extends previous economic models by dropping the limiting assumption of zero enforcement costs. These models generally abstract from problems of fine enforcement and assume that all fines are collected and that enforcement costs are zero. Criminologists and practitioners, on the other hand, have been very much aware of enforcement costs. Imprisonment for fine default is particularly costly and exacerbates the crowded prison conditions that exist in many countries. Tabular data and 18 references. (Author abstract modified)