Peat is a notoriously problematic soil having high-water content, a large void ratio, and weak engineering properties. Thus, it needs to be treated before utilization to withstand structural stress. On the other hand, the amount of waste tires increases exponentially due to the high demand for vehicles. Therefore, they need to be sustainably recovered and recycled rather than disposed or incinerated. This study aimed to stabilize the peat collected from Sungai Bidut, Sibu with crumb waste tires (CRT). Different percentages (15, 20, and 25) of CRT were used to determine its effect on peat strength improvement. The effectiveness of CRT was assessed using mechanical testing i.e., unconfined compressive strength (UCS). The optimum amount of CRT was also concluded based on the UCS by comparing it with the untreated peat. Finally, the morphological change of peat in depth was studied by scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results revealed that the optimum compressive strength of the peat soil is achieved with the incorporation of 15 CRT. The highest UCS of 99.73 kPa was recorded with the use of 15 CRT and the strength decreases with the increasing use of CRT. The microstructural tests show that peat becomes more compact and humified with depth. Moreover, peat at any depth is mainly composed of carbon (C) and oxygen (O) and the small proportion of Silicon (Si) indicates less amount of clay particles. © 2022, Horizon Research Publishing.