The 1980s and 1990s have witnessed substantial changes in the U.S. swine industry. The industry structure has shifted from relatively large numbers of hog (Sus scrofa) farm operators producing for open markets to fewer and larger farm operators raising hogs under contracts for intermediary firms or meatpackers. This shift has resulted in debates over whether the movement from independent to contract hog production has proven beneficial or detrimental for manure management and pollution control. To shed light on these debates, we surveyed by mail independent and contract hog producers in the southern USA and gathered data on the structure of their farms, their opinions on environmental issues in the hog industry, and their manure management strategies. The survey results indicate that contract producers maintain higher animal units per hectare and spread the hog manure over smaller areas than do independents. However, contract producers also realize they are pushing the adsorptive capacity of their farms and adopt ameliorating and monitoring technologies at higher rates than independent producers. We conclude that market structure is an important determinant of farm structure and environmental management regime, and that adoption of pollution control technologies is not equivalent to environmental performance. Abbreviations: AEU, animal equivalent unit. PROFOUND STRUCTURAL CHANGES have taken place in U.S. agriculture in the 1980s and 1990s. Increasingly, processing firms and production operations are becoming more closely linked. This has happened through vertical integration, where firms own production and processing outright, or through contracting, where processing firms or intermediary buyers contract with growers to grow out products (Welsh, 1996). Contract production is becoming increasingly common in the hog industry. Current estimates of contract hog production vary. However, many analysts predict that in the near future the hog industry will mirror the poultry industry with the vast majority of production under contract (Smith, 1998). An important issue in regard to increased contract production is the shift in control over decision-making from the farm level to firms that pay farm-level workers to grow products. Producers who enter into production contracts give up some control over the structure of their farms, as well as over the quality of farm inputs and how inputs are used in production (Welsh, 1997). For example, under hog production contract regimes, the contractor often provides animals, feed, veterinary services, and marketing and transport services, as well as technical expertise and supervision of the production process. This means the producer does not control important aspects of production that may influence how that farm performs in a number of areas. One of these areas is environmental performance of the hog operation. Here we explore the issue of contract vs. independent production in the hog industry and the potential meaning of this dichotomy for environmental management of the farm. We first discuss two opposing viewpoints of contract and independent production regarding environmental performance or pollution control. Then, using data obtained from a mail survey of hog producers in the southern USA, we try to provide some insight into how different production regimes interact with the natural environment in which they operate. Finally, we make some conclusions about determinants of farm-level environmental management, and how we can evaluate such management in future discussions about the changing structure of agriculture and the need for controlling pollution from agricultural operations.