Synovial sepsis represents a major cause of morbidity and mortality in foals; however, there are no studies focusing on foals particularly at risk during the first 2 months of life. Our objective was to analyse outcome in foals aged <2 months with haematogenous septic arthritis and to identify prognostic factors and compare the effects of two different lavage procedures on outcome. Sixty foals with synovial sepsis were used for our retrospective study in which medical records, online data and telephone interviews were utilised to analyse prognostic factors, and determine short- and long-term survival and athletic performance of foals treated at Evidensia Equine Specialist Hospital, Helsingborg, between 2008 and 2014. Overall survival to discharge was 80% (48/60). Time to long-term follow-up ranged from 6 months to 6.5 years. Forty/60 (67%) horses survived long-term. Four/8 (50%) of the nonsurvivors at long-term follow-up had been subjected to euthanasia due to sequelae of joint sepsis. Of the long-term survivors, 37/40 (92.5%) achieved athletic soundness. Overall long-term outcome for athletic soundness was 37/60 (62%). Prognostic factors based on historical, clinical or laboratory data, or the use of through-and-through needle lavage compared to endoscopic lavage as the first procedure, could not be identified. The present study demonstrates a more favourable prognosis than previously reported, with 80% of foals with synovial sepsis surviving to discharge, and approximately 60% achieving athletic soundness. However, the study was limited by a small population size, which may account for the failure to verify statistically significant prognostic factors.