This paper reports findings of a study that captures cost estimation practices and techniques prevalent in the construction industry in Oman. It also identifies the success and risk factors that are encountered in the cost estimation process. Eighty structured questionnaires were distributed to some professionals working in construction projects, selected randomly from large and medium size enterprises across the Sultanate. A response rate of 56% was achieved. The results showed that the unit rate method, the use of historical data and benchmarking are the most common methods used for cost estimation. Success and risk factors as reported by respondents were analyzed and ranked accordingly. The main sources of risk were reported by respondents as "Unclear reading and understanding of specifications", "Lack of clear documents of the project scope of work", and "Unavailability of Resources". This study provides an insight understanding of revealed practices and techniques and globally share the findings with researchers and professionals.