Avoidable hospitalizations for ambulatory care sensitive conditions (AH-ACSCs) identify health problems that could be avoided by improving primary health care (PHC). On the basis of hospital discharges from Argentine public sector facilities, an expert panel convened to define a list of AH-ACSCs for children and adults. AH-ACSCs represented less than 30% of hospitalizations. Compared with country averages, poorer districts showed large differences in trends for adults but not for children. Despite that AH-ACSCs have demonstrated empirical validity to evaluate health system performance, its implementation to assess PHC in countries like Argentina, with pluralistic and fragmented health care systems, remains a big challenge.