Occupational health and safety practices are designed to handle accidents and illnessesrnthat occurred during work and due to the effects of work. To manage the issuernInternational, regional and national organizations have developed standards, directivesrnand guidelines. Construction is one of the highest occupational illnesses causing sectorrnthat result in several fatal and nonfatal accidents. The objective of this paper is to assessrnpractices and challenges of the implementation level of occupational health and safetyrnstandard intended for construction sector in selected building construction firms found inrnAddis Ababa. In presentation of results descriptive approach is followed based onrnquantitative and qualitative analysis of data collected from twenty one randomly selectedrngrade one construction firms. From the willing firmsâ€™ persons having direct involvementrnin the area including safety and health officers, project managers and other staffs arernidentified and administered with the questionnaire. The data is collected throughrnquestionnaire inquiring the awareness, practices and challenges of occupational healthrnand safety standard implementation. The collected data is analyzed using SPSS statisticsrntool. The study showed that only nearly half of the participating firms know about thernavailability of the standard and many of them are not using it. In the other hand thernrequirements stated in the standard and in other literatures are not well placed and notrnpracticed properly. Integration of occupational health and safety in business activities, ofrnlack of budget, absence of planning and identification of hazards and participation ofrnworkers in this activities are major findings of the study. It is also observed that nearlyrnhalf of the participating firms do not have a function that handles occupational healthrnand safety issues. The major challenge raised from the participating firms is lack ofrnmanagement commitment in implementing the requirements and practices in constructionrnsites. As a recommendation the firms should use the standard and apply the requirementsrnand other practices to save the life of their workers and the resource wasted in relation tornaccidents. Finally this paper provides a highlight on occupational status of participatingrnfirms which will be used as an input for further detail study on the overall status of thernfirms with this respect.