There were an estimated 5.9 million deaths among children under five years in 2015, with infectious diseases accounting for almost half (51.8%) of these deaths. Pneumonia was the leading cause of infectious deaths, with 60% cases concentrated in 10 countries in Sub-Saharan Africa and South Asia. In 2014, pneumonia was the leading cause ofdeath amongchildren under five years in Kenya. Kenya is one of the countries that have not yet adopted community management of pneumonia as recommended by UNICEF/WHO in 2013. As such, management of pneumonia cases remains health facility based. Much delay however, has been observed by caregivers in seeking care at the health facilities. This study sought to establish the determinants of health facility consultation among caretakers of children under five years of age with ARI. This was an analytical cross-sectional study carried out in Githunguri SubCounty from November to December 2014. A total of 323 mothers of children under five were included in the study. Simple random sampling was used to select the study participants. The dependent variable was ―timing of health facility consultation for ARI‖. Structured questionnaires were used to collect data on socio-demographic and household factors, pneumonia knowledge and facility factors. Focused Group Discussions and Key Informant Interview guide were used to collect qualitative data. Informed consent was sought from the study participants. Data was analyzed using Statistical package for social sciences (SPSS) software version 20.Univariate, bivariate and multivariate analysis was done to show frequency distributions and associations between variables. The prevalence of ARI in Githunguri Sub-County among children under five years was 240 (74.3%). More than half 149 (62.1%) delayed consulting a health facility for ARI.Caretakers delayed seeking care for their female child than their male child (p = 0.036). There was more delayed facility consultation for ARI when fathers made on care seeking compared to mothers (p =0.016). Poor knowledge of pneumonia symptoms was associated with delayed health facility consultation (p = 0.007). Facility factors that influenced health facility consultation were, high cost of care in the previous facility visit (p = 0.011) and long waiting time before assistance at the health facility (p = 0.023). On logistic regression, the strongest determinant of ―health facility consultation for ARI‖ was having waitedfor >1 hour before service provision (delayed assistance) at the health facility (OR =0.25; C.I (0.12- 0.56); p = 0.001).In conclusion, delayed health facility consultation is rampant in this community, mainly due to perceivedlong waiting time before service provision at the health facility. The study therefore, recommends need to devise strategies to improve efficiency of services at all tiers of health care by the Ministry of Health. In addition, there is need for health education on recognition of pneumonia symptoms and on prompt appropriate care seeking to caretakers by the County health officers.