Both silicone and latex single-balloon Foley catheters are available for cervical ripening but no literature exists to compare them. Local experience suggested more frequent insertion-related accidental rupture of the membranes (acROM) with silicone. To compare the performance of silicone versus latex catheters with respect to acROM and other outcomes. Women undergoing outpatient Foley catheter cervical ripening were randomised to a silicone or latex catheter. Data were collected on the primary outcome, acROM, and secondary outcomes including catheter insertion failure, unplanned hospital admission and patient-reported discomfort, together with intrapartum fever and antibiotics for suspected chorioamnionitis along with general obstetric and neonatal outcomes. Among 534 recruited women, acROM was significantly more common with a silicone compared to a latex catheter at 7.2% (19/265) versus 1.5% (4/269) (relative risk (RR) 4.8; 95% CI 1.7-14.0). Insertion failure was significantly less common with silicone than latex at 2.6% (7/265) versus 9.3% (25/269) (RR 0.3; 95% CI 0.1-0.6). However, when the alternative catheter was subsequently tried, the final failure rates were 1.9% silicone (5/265) versus 2.6% latex (7/269). Insertion-related hospital admission was higher with silicone at 9.4% (25/265) than latex at 4.8% (13/269) (RR 2.1; 95% CI 1.1-4.1). All other obstetric outcomes were similar between the groups. When used for cervical ripening, a silicone Foley catheter is associated with a higher rate of acROM than a latex catheter but a lower rate of insertion failure. It may, therefore, be reasonable to attempt insertion with a latex catheter initially and manage insertion failures with a silicone catheter.