Background and Aim: Time compressed spe­ech test is one of the most useful monaural tests for evaluation of central auditory processing disorder. For developing the time compressed sentences test, the compression rate of the sen­tences must be set so that the average speech comprehension score is about 90% in normal individuals and can challenge central auditory processing system sufficiently so subjects with auditory processing disorders could be identi­fied. Therefore, the aim of the present study was finding the appropriate compression rate for developing compressed sentences test in Persian. Method: Initially, two 10-sentence lists were prepared based on the experts’ opinion and were compressed by the amount of 60, 65, 70, 75 and 80% using Praat software. Compressed sentences were tested on twelve 18–25 year-old normal individuals and the speech comprehen­sion score in different compression rates was compared and the compression rate in which the average score was approximately 90% was reported as an appropriate compression rate for developing time compressed sentences test in Persian. Results: 70% compression rate was able to cre­ate an average score of 95.27% (± 3.31) and 93.6% (± 7.17) in the right and left ear, res­pectively. Conclusion: Results showed that the compre­ssion rate of 70% was appropriate rate for dev­eloping the test in the Persian language.