OBJECTIVES: Type II Diabetes Mellitus (DM) is exponentially growing in Chile. A recent reform aimed at reducing inequities in healthcare in the country, but the gap between social groups continues to grow. We aimed at exploring the existence of under-diagnosis of type II DM in adult population in Chile. METHODS: Secondary analysis of cross-sectional Chilean Health Survey 2009-2010 (n=4767 adults, weighted sample: 13,347,316). We compared the proportion of adult population self-reporting type II DM against the proportion with altered fasting glycaemia (value >126mg/dl, Chi-square test) and then assessed the socio-demographic characteristics of those having the condition but ignoring it. For population-representative analysis we used Stata 12.0. RESULTS: