An elevated body mass index (BMI) may make venipuncture more difficult, potentially impacting the use of home infusion (HI) and self-infusion (SI). We sought to determine whether above-normal BMI is associated with decreased use of HI treatment and SI of clotting factor concentrate among haemophilic persons. We analysed data from 10 814 male patients with haemophilia A and B (45% with severe disease) aged 6–79 years enrolled in the Centers for Disease Control and Prevention Universal Data Collection surveillance project between 1998 and 2008. Associations between the use of HI and SI and BMI were evaluated using logistic regression. Fifty per cent of haemophilic men were overweight or obese, similar to rates reported among the general US population by the 2007–2008 National Health and Nutrition Examination Survey [Flegal, KM et al., JAMA 2010;303:235–241;]. Twenty per cent of children and 22% of teens were obese, as were 28% of adults [Ogden, CL et al., JAMA 2010;303:235, 242]. Overall, 70% of the study sample used HI; 44% of those who used HI also used SI. Overweight and obese men were each less likely to use HI than those of normal weight [odds ratio (OR) 0.8; 95% confidence interval (CI) 0.7–1.0 and OR 0.7; 95% CI 0.6–0.8 respectively]. Obese teens and adult men were also less likely to practice SI than teens and adults of normal weight (OR 0.8; 95% CI 0.7–0.9 for each). We conclude that overweight and obese haemophilic men are less likely to use HI and obese men are less likely to use SI than their normal-weight counterparts.