The study evaluated the impact of the ISO 9001:2008 International Standard on Project Success. Project Success was defined from the viewpoint of the contractor; and Cost, Billing, Profitability, Schedule, Quality, Safety and Environmental performance are measures of project management success.  Case study research was conducted in a South African construction firm which evaluated the impact of the ISO 9001:2008 International Standard on two projects within the firm. Data collection was enabled through document review, a survey and performance index calculations. The ISO 9001:2008 clauses that were determined to have the most impact on project success were ISO Clause 4 Quality Management System and ISO Clause 5 Management Responsibility. The case study projects were also deemed successful by the determination of the Project Management Success performance indices, using actual project data.