PurposeComplying with the code of conduct by professionals in the construction industry worldwide has become a significant issue over the years. This has led to projects' failure, leading to losses to both the client and contractors. The study's objective is to identify the challenges of construction professionals in complying with their code of conduct and preventing corrupt practices.Design/methodology/approachQuantitative approach was used to collect empirical data by sending questionnaires to 56 construction professionals in South Africa. Data gathered were analysed through Excel statistical tool. Mean values were calculated for the quantitative data, whilst thematic content analyses were used to generate frequencies and percentages for qualitative data.FindingsThe findings indicate that construction professionals experience many unethical issues in their work duties such as inflated tender prices, overpricing the rates, tender-based kickbacks, bribes for projects, unethical methods of project execution, use of lower grade materials than specified, discrimination, among others. However, issues such as greediness, acceptance of corruption as usual practice, lack of knowledge about the code of conduct, the only way to get contracts, part of the process, and peer pressure create a challenge in complying with the code of conduct and preventing corrupt practices among construction professionals.Practical implicationsConstruction professionals face many unethical and corrupt practices in their project management and execution, which they cannot overcome due to many factors. Therefore, there is the need to sensitise the professionals in the construction industry regarding their code of conduct as well as the danger associated with engaging in corrupt practices in their work and their implication on project performance.Originality/valueThe findings give an insight into the critical factors curtailing the construction professional's ability to comply with their code of conduct and be corrupt-free in their line of duty. Thus, professional associations can use the findings in guiding their members.