Rapid urbanization has profoundly altered environmental conditions, presenting new challenges to forensic entomology by influencing key insect evidence used to estimate the postmortem interval (PMI). This study examined the impact of building height on necrophagous insect activity, diversity, and succession in Kafrelsheikh, Egypt. Guinea pig carcasses were placed at three height levels ‒ ground level (L1, 0 m), intermediate (L2, 20 m), and high-rise (L3, 50 m) ‒ and monitored for decomposition and insect colonization. Decomposition rates remained consistent across all heights, whereas insect density and diversity significantly declined with increasing elevation (e.g., mean insect abundance dropped from 84.59±6.12 at L1 to 15.85±3.14 at L3, and the Shannon diversity index from 2.7±0.08 to 2.2±0.12), likely due to stronger air currents, greater temperature variability, and limited accessibility at higher levels. Early colonizers, including Musca domestica and Sarcophaga argyrostoma, showed delayed arrival of one to several days or were completely absent at elevated sites, accompanied by notable shifts in species composition and succession timing. Statistical analyses (one-way ANOVA: F(2,15) = 68.21, p<0.001, η² = 0.76; Kaplan–Meier log-rank test) confirmed significant elevation-dependent differences in insect activity. These findings highlight the need for height-adjusted PMI estimation models in urban forensic investigations, particularly in high-rise environments.