The behavior of three genotypes of gilts were compared in an English-style intensive outdoor production system or an intensive indoor system, each operated on a common production schedule. The genotypes investigated were PIC Camborough-15 (C-15); PIC Camborough-Blue (CB); and York x Landrace (YL). Behavior as defined and recorded were mutually exclusive, including: chewing, rooting, standing, sitting, drinking, rubbing, walking, and for outdoor gilts wallowing and grazing. No significant main effects of genotype were found. Gilts kept outdoors were more active and spent more time chewing objects, with less time sitting than gilts indoors. The oral/nasal chewing observed in confined, pregnant pigs was much lower in frequency than similar environment-directed oral/nasal behaviors observed outdoors. Genotypes did not differ in behavior; however, the genotype by environment interaction was significant for lying (resting) behaviors. Outdoor-kept gilts spent less time lying than indoor gilts, but the effect was less pronounced for C-15 than for CB or YL, genotypes. The few significant genotype and genotype by environment interactions indicated that these genotypes generally express similar behavior. However, the outdoor environment seemed to induce more oral/nasal behaviors than the indoor production system.