<p class="abstract"><strong>Background:</strong> Radon is an important natural radioactive factor harmfully, because radon is radioactive gas comes from the natural decay of uranium series deposits in soil, which is harmful on human and environment.</p><p class="abstract"><strong>Methods:</strong> <span lang="EN-IN">The radon concentrations and exhalation rate were measured using passive technique with CR-39 and LR-115 detectors in twenty soil samples from and around Manzala Lake in the North Nile Delta, Egypt. </span><span lang="EN-IN"> </span></p><p class="abstract"><strong>Results:</strong> From the results the average value of radon concentration ranged from 874.51 to 136.99 Bqm^-3.</p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">The present study can be used as reference information to detect any harmful radiation that would affect the human and assess any changes in the radioactive background in the studied area. </span></p>