Plasmodium vivax remains widespread, and outside of Africa, it is becoming the dominant cause of malaria. There is increasing recognition that recurrent vivax malaria is associated with recurrent symptomatic illness and anaemia with attributable morbidity and mortality. Recurrent P. vivax can arise from recrudescence (treatment failure), reinfection (new infections from an infected mosquito bite) and relapse (reactivation from dormant liver stages). Whilst it is currently impossible to differentiate reliably between these alternatives, early recurrence is more likely to be due to recrudescence, whereas later recurrences are more likely to be due to relapse and reinfection. The risk, frequency and timing of recurrence is dependent upon host, parasite and drug factors including: antimalarial drug resistance, the pharmacokinetic profile of the antimalarial agents administered, the use of hypnozoiticidal drugs and the endemic setting (relapse patterns and endemicity). The relative contributions of these risk factors have not been comprehensively evaluated. If the risks and benefits of radical cure are to be quantified, there was a need to further understand the factors that impact on recurrence, with and without radical therapy.