Background This study considers the factors that affect service provision for individuals who present to out-of-hours (OOH) primary care services in the Republic of Ireland and Northern Ireland. The organisations under consideration are known as OOH co-ops. Specifically, an individual can potentially receive one of four services: nurse advice, doctor advice, a treatment centre consultation or a home visit. Aim The principal aim was to investigate whether service provision was consistent across co-ops once patient characteristics, patient complaints and other covariates were controlled for. In this paper, service provision was seen as a necessary but not sufficient condition for quality. Methods A multinomial logit approach was used to model the choice between the three services offered by co-ops. Results The results indicate that service provision was relatively homogenous across co-ops. Conclusions Quality was consistent across co-ops in terms of service provision. Therefore the next step is to consider whether quality within the treatment received varies. Nevertheless, the result provides some support for using OOH co-ops as a means to provide OOH primary care.