Underutilization of healthcare is common among rural and low-income population segments in countries with lower income or inequitable income distribution. Micro health insurance units (MIUs) are created by informal sector groups because people cannot access health insurance or are dissatisfied with the programmes they can access. The policy choice to support MIUs relies on evidence that affiliation with these schemes increases healthcare utilization. This article examines new evidence of the association between affiliation with MIUs and healthcare utilization. We analyzed field data collected in 6 MIUs in the Philippines in 2002 (through a household survey encompassing 890 insured- and 1063 uninsured households). The two cohorts did not differ in demographic parameters, and differed only marginally in income and education levels, both higher amongst the insured. Insured persons reported higher hospitalization rates, higher rates of professionally-attended deliveries, lower rates of delivery at home, a higher frequency of primary-care physician encounters, a higher rate of diagnosed chronic diseases, and better drug compliance among chronically ill. Increased utilization by the insured is not due to adverse selection, judging by two facts: morbidity of the two cohorts, as assessed by a proxy indicator (the reported number of episodes of illness) did not differ; and rates of deliveries were even slightly higher among the uninsured. We conclude that MIUs in the Philippines can alleviate underutilization of heath care.