Background: Health Information system is one of the building blocks of health system and basic for decision-making among the health system building blocks. The overall design of the community health information system innovation is to simplify the community health extension worker’s role and focus on the delivery of health care at the community level by identifying community health needs easily. Reform has taken significant measures to remedy the lack of routine health information that has limited the quality of treatment, planning, and management processes, as well as decision-making by managers at all levels of the health system. But data quality is not at the required level. Though there are some studies conducted on quality of data generated at health facilities and culture of utilization of data, there is only one study conducted to show extent of implementation of community health information system. So, this evaluation fills the information gap on extent of implementation in terms of input, activity and output. Objective: To evaluate the extent of community health information system implementation at Ayehu Guagusa in 2021. Methods: Convergent parallel mixed study design was used. The evaluation approach was formative and the availability, compliance and consistency were evaluation dimensions. Resource inventory tool, document review template, an observation checklist and key informant interview guide were used to collect data. Lottery method was used to select six health posts. Then 846 family folders proportionally allocated to each health post and selected by using systematic random from each health post. key informants were participated in the study based on their expertise and experience. Data quality was assured before, during and after the data collection process. Quantitative data were entered and analysed by SPSS 23. The qualitative data were recorded, transcribed, translated, familiarized, coded and finally conceptualized to themes. Result: the overall implementation was 63.7% which is poor according to judgment criteria. Availability of CHIS tools in the district was 79.4%. The overall compliance of implementation with standard guideline was 37.4%. The consistency of data in different sources was 83.4%. Conclusion: The overall implementation was poor according to judgmental criteria and low compared to national expectations. Weak supportive supervision and feedback system, shortage of resources, difficulty of understanding English language and lack of training were major reasons. So, it is better to improve the operation by giving attention on identified reasons.