This study aims to evaluate the stability of immediate implant placement in the lower posterior region. Ten patients with mandibular hopeless prognosis teeth were recruited. Ten dental implants were placed immediately in fresh sockets with alloplastic bone substitute material. The appointments of the follow-up were made for recording the implant stability quotients (ISQ) values immediately after the implant placement (W0) and one week (W1), two weeks (W2), four weeks (W4), six weeks (W6), eight weeks (W8), ten weeks (W10), and 12 weeks (W12) after the implant placement. At six months after the implant placement, the final restoration was delivered. Multivariate tests were used to analyze the relationship of the ISQ values at different points in time. The confidence interval was set at 95%, and P-value < 0.05 was interpreted as statistically significant. All mandibular implants were successfully integrated. The mean ISQ value after the implant insertion was 73.85 ± 5.11. The ISQ value was dipped at four weeks at 72.95 ± 5.26. There were statistically significant differences between each point of experimental time (p=0.039). In this preliminary study, the implant installation in a fresh mandibular socket with a regular diameter implant found favorable outcomes. The posterior region’s immediate implant placement was challenged because of socket morphology, limited space of site preparation below root apex, and anatomical structure. Hence, the cone-beam computed tomography (CBCT) would help to reduce these complications. It provided critical information prior implant surgery. The implant stability is time-dependent. The ISQ value of one-stage immediate implant placement in the mandibular posterior teeth could be achieved over 60 in both primary and secondary stability. It gradually decreased into the minimum point at the fourth week and then continuously increased until the 12^th week.