BACKGROUND: Underutilization of PhilHealth benefits undermines the effective distribution of public resources. To formulate effective strategies, the factors affecting the utilization of members must be studied.

OBJECTIVES: To (1) assess the rate of underutilization of inpatient benefits and (2) determine the association of chosen factors with PhilHealth underutilization of selected member groups in three barangays in Manila.

METHODS: The study was done in selected Barangays in Manila. Using the Expanded Program on Immunization (EPI) method of sampling, a sample size of 147 households were obtained and interviewed  for the study. An interview guide was used to gather the data needed for analysis. Chi-square test was then used to determine existing associations between underutilization and the chosen factors.

RESULTS AND CONCLUSION: The chi-square test of association revealed that gender (p-value=0.034), income (p-value=0.026), and type of membership (p-value=0.027) are significantly associated with underutilization. Females and paying members were found to be more frequent users. Gap between the utilization and underutilization rates was found to be greatest in the lowest income groups. 'Lack of knowledge on filing claims' (p-value<0.001) and on benefits (p-value<0.001) were also identified as significant predictors of underutilization. Results showing a significant proportion of household experiencing insurance underutilization highlight the need for NHIC to create new and/or improved mechanisms that will enable it to extend its reach to the people.