Laminar airflow systems are universal in current orthopaedic operating theatres and are assumed to be associated with a lower risk of contamination of the surgical wound and subsequent early infection. Evidence to support their use is limited and sometimes conflicting. We investigated whether there were any differences in infection rates (deep and superficial) between knee and hip arthroplasty cases performed in non-laminar and laminar flow theatres at 10 year follow-up. Between 2002 and 2006, 318 patients underwent knee and hip arthroplasty in a non-laminar flow theatre. Prospectively collected local arthroplasty audit data was collected including superficial and deep infection, revision for infection and functional outcomes. A cohort of patients from the same time period, who underwent knee and hip arthroplasty in a laminar flow theatre, were matched for age, sex, body mass index (BMI), operative approach, implant and experience of surgeon. Superficial infection rates were lower overall in the non-laminar flow theatre (2.2percnt; versus 4.7percnt;), with a significantly lower superficial infection rate for knee arthroplasty performed in the non-laminar flow theatre (2percnt; versus 6.9percnt;). The deep infection rates were similar (1.3percnt; vs 1.9percnt;) for both laminar and non-laminar flow theatre respectively. Revision rates for infection were similar between both groups (0.9percnt; in non-laminar flow theatre vs 0.3percnt; in laminar flow). Whilst the causes of post-operative surgical site infection are multifactorial, our results demonstrate that at long –term follow-up, there was no increased risk of infection without laminar flow use in our theatre