Background: South Africa has one of the highest HIV prevalence rates in the world and high contraceptive use among women aged 15–49 (65.3%). Family planning (FP) services remain a missed opportunity to integrate services for HIV. Recent reviews highlighted the lack of rigorously conducted studies of the effectiveness of integrated services. A cluster randomised trial (CRT) was conducted to evaluate the effectiveness of a model of integrating HIV into FP services compared with standard practice. The study sought to measure the effect of integrated services (Balanced Counselling Strategy Plus) on HIV testing in the previous year; use of dual protection and quality of HIV and FP care. Methods: A CRT was conducted in 12 clinics in North West province, South Africa. Structured clientprovider observations (CPOs) and client exit interviews (EIs) were conducted preintervention and one year later with FP clients aged >=18 years. Primary outcomes were condom use at last sex and testing for HIV in last year. The quality of care scores were constructed to assess HIV and FP quality of care. Analysis of effectiveness used statistical methods for CRTs. Findings: A total of 1,111 CPOs and 1,111 EIs were completed at baseline and 1,223 CPOs and 1,264 EIs at follow-up. At follow-up 33.2% of women in the intervention arm had tested for HIV in the last year compared with 21.4% in the control arm; RR=1.56 (95%CI: 1.13– 2.15; p=0.01). Condom use at last sex was 43.7% in the intervention arm and 39.4% in the control arm; RR=1.10 (95%CI: 0.85–1.43; p=0.14). Interpretation There was strong evidence of higher frequency of HIV testing among FP clients at intervention clinics. However, condom use at last sex was similar across intervention and control arms. All QOC scores were higher in intervention clinics, but there was substantial variation across clinics and these differences were not significant.