INTRODUCTION: The timing of implant placement after tooth extraction has been a matter of discussion in dental implant treatment. Primary stability of the implant placed can be measured by the resonance frequency analysis (RFA) which is used to compare the primary stability of immediate and delayed immediate placed implants. OBJECTIVES: This study was designed to compare between primary stability of immediate placed implants and delayed immediate placed implants using resonance frequency analysis device in mandibular single rooted teeth. MATERIALS AND METHODS: Ten patients were selected from Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Alexandria University divided into two groups, Group A: Five patients indicated for extraction of single rooted teeth had undergone implant placement immediately after tooth extraction (Immediate implant placement). Group B: Five patients indicated for extraction of single rooted teeth had undergone implant placement two weeks after tooth extraction (Delayed immediate implant placement). RESULTS: For group A patients the average mean and standard deviation of the primary stability of the placed implants was 61.75 ± 8.21 ISQ units while for group B patients the average mean and standard deviation of the primary stability of the placed implants was 67.38 ± 11.59 ISQ units. After comparing these results it was shown that the average mean and standard deviation of the primary stability of all cases of group B is greater than the average mean and standard deviation of the primary stability of all cases of group A, which results in a t-value (student t-test) of 0.792 and the p- value of the study was 0.458 which is statistically insignificant. CONCLUSIONS: There is no significant difference between the primary stability of immediately placed implants and delayed immediate placed implants