Background
Delivery at health institutions under the care of trained health-care providers and utilization of postnatal cares services plays vital roles in promoting child survival and reducing the risk of maternal mortality. More than 80 % of maternal deaths can be prevented if pregnant women access to essential maternity cares like antenatal care, institutional delivery and postnatal care services. Thus, this study aimed to assess institutional delivery and postnatal care services utilizations in Abuna Gindeberet District, West Shewa, Oromiya Regional State, Ethiopia.

Methods
A community-based cross-sectional study design was employed among 703 randomly identified mothers of Abuna Gindeberet district in March, 2013. Data were collected through interviewer-administered questionnaires and analyzed using SPSS version 16.0. Descriptive, bivariate and multivariate analyses were used to determine prevalence and to identify associated factors with institutional delivery and postnatal care, considering p-value of less than 0.05 as significant. The results were presented in a narrative forms, tables and graphs.

Results
One hundred one (14.4 %) of mothers gave birth to their last baby in health institutions. From 556 (79.1 %) of respondents who heard about postnatal care services, only 223 (31.7 %) of them utilized postnatal care services for their recent childbirth. From the total postnatal care users, 204 (91.5 %) of them took the services from health extension workers. Decision-making styles, household distances from health institutions, household being model family and ANC services utilizations were found to be statistically significant with both institutional delivery and postnatal care services utilizations. But educational status of husbands was statistically significant with only postnatal care services utilizations.

Conclusions
Both institutional delivery and postnatal care services utilizations from health institutions were low. Decision-making styles, household distances from health institutions, household being model family and ANC services utilizations were the common factors that affect institutional delivery and postnatal care services utilizations from health institutions. Therefore, giving attention to the identified factors could improve and sustain institutional delivery and postnatal care services utilizations from health institutions.