AbstractWe assessed cystic fibrosis (CF) knowledge and emotional consequences of CF population testing 18 months after screening was offered. Questionnaires were sent to 593 individuals and 353 responded (59.5%). All respondents had sound knowledge of CF disease, although carriers were more likely to correctly state the pattern of CF inheritance and CF carrier rate in Australia. Eleven of 47 carriers falsely believed they were only very likely to be carriers, while nearly a third of test‐negative individuals falsely believed they were definitely not carriers. Imprecise recall of the meaning of results may be due to memory loss over time, simplification of result meaning and minimization of risk. The Health Orientation Scale (HOS) was used to assess emotional consequences of CF carrier testing 18 months after testing. Both carriers and test‐negative individuals thought most carriers would experience more negative feelings than most non‐carriers. Carriers experienced less positive feelings about their test result compared to non‐carriers. Interestingly, the carriers' own feelings about their result were more positive compared to how they thought most carriers would feel. These results suggest that carriers experience minimal adverse psychological effects, although a negative social stigma may be attached to carrying the CF gene mutation. © 2003 Wiley‐Liss, Inc.