Prior to weaning, many piglets die from crushing, chilling, starvation diarrhea and weakness. Piglets often die from crushing by the sow when she lies down after sitting. The objective of this study was to determine the amount of heritable genetic variation of sitting behavior. A total of 312 pigs from 62 litters were given ad libitum feed and water. Frequency and occurrence of sitting were summarized from 24-h video records. Heritability estimates (h2) were calculated for these traits using a full-sib analysis. The h2 for the occurrence of sitting was 0.41 ± 0.14 and for frequency of sitting was 0.43 ± 0.14. Genetic correlation between frequency and occurrence of sitting was 0.84 and the phenotypic correlation was 0.68 (P < 0.01). Sitting behavior was moderately to highly heritable indicating possible favorable selection against occurrence of this trait. Genetic selection against sow sitting could potentially decrease mortality rates among piglets, increase production and decrease costs for pork producers.