Kisspeptin regulates reproduction by activating gonadotrophin-releasing hormone (GnRH) neurons through its receptor, Kiss1r. Kiss1r knockout (KO) mice develop an obese and diabetic phenotype compared to wild type (WT) littermates. We used Kiss1rKO and WT male and female mice to investigate the relationship between absent kisspeptin signalling and locomotor behaviour by allowing mice free access to running wheels (Lafayette Mouse Activity Wheel Chambers). These studies were also performed following gonadectomy (GDX), to control for gonadal steroids. We examined the real-time characteristics of wheel running over a 3-week period and its flow-on effects on body weight. In intact males, there was a 90% reduction in total distance travelled per 24h in KO mice compared to WTs (WT, 6363±643m; KO, 652±219m; P<0.0001). Moreover, the circadian pattern of wheel running activity (dark phase activity) clearly present in WT mice was severely diminished in KOs. However, in GDX males there was no difference between WT and KOs, (WT, 1652±474m; KO, 998±219m). In intact females, there was a 77% reduction in total distance travelled per 24h in KO mice, compared to WTs (WT, 6030±747m; KO, 1379±364m; P<0.004). In OVX females there was no difference between KO mice and WTs (WT, 4150±1367m; KO, 3117±830m). Body weight analysis showed that wheel running prevented the weight gain normally attributed to the Kiss1rKO mouse. In fact, in GDX males and females (at days 21 and 22 of wheel running) KOs were significantly lighter than WTs (at day 22: Males, WT 28.67g; KO, 23.70g; P<0.05; Females, WT, 27.38g; KO, 23.30g; P<0.05). We show the reduced locomotor activity in male and female Kiss1r KO mice is dependent on gonadal sex steroid status. Whether absent kisspeptin signalling acts as a regulator of voluntary activity is debatable but patterns of locomotion behaviour could be disrupted, potentially involving circadian rhythm, this is under further investigation.