Swine vocalizations may provide information on behavioral states. Previous studies have reported that an increased total number of high calls (≥1000 Hz) may be an indicator of a negative state in male pigs (Kluivers-Poodt et al., 2011). However, few studies have investigated if vocalizations differ between male and female pigs. Therefore, the objective of this study was to investigate differences between barrow and gilt vocalizations during a human approach test (HAT). Twenty barrows and 20 gilts were tested over two consecutive weeks. Each pig was individually tested in an arena with an unfamiliar human for 10 minutes. Digital audio recordings of pig vocalizations during HAT were captured with a Marantz recorder. Raven software was used to produce spectrograms and manually identify vocalizations. Two call categories were developed based on published literature: low (< 0.01). These data suggest barrows and gilts differ in their vocal response to HAT.