Seven organophosphorus compounds (OPs) were measured in urban fine and coarse particulate matter (PM) collected from two sites of Nanjing (XCNUC), China and Islamabad (APHSP), Pakistan. The fine PM mass at APHSP site was significantly higher (p=0.005) in the spring (mean 22.5μg/m3) than in the summer (mean 12.7μg/m3). The total concentration, ∑7OPs, of samples collected at APHSP was found significantly higher in coarse (range 672-47621pg/m3) than in fine PM (range 1200-15213pg/m3); while ∑7OPs from XCNUC in fine (range 1696-15063pg/m3) and coarse PM (range 2053-5379pg/m3) were statistically different in samples during summer, based on two-sample t-test at 0.05 confidence interval. Seasonally, ∑7OPs was found to be higher in the samples of Nanjing (9510±3633pg/m3) in the summer than in the spring. In contrast, the samples of Islamabad had higher ∑7OPs (25558±16255pg/m3) in the spring than in the summer. Tri(chloropropyl) phosphate (TCEP) was found at higher concentration than any other OPs in the samples from the XCNUC site. Triphenyl phosphate (TPhP) was found at extremely high levels from APHSP, which may attributed to its use in jet fuel. Most of the ∑OPs concentrations were found significantly different in both PMs at both sites due to their diverse sources. Both sites showed strong correlation of ∑OPs with TCEP in both PMs, indicating similar mode of transfer from sources like plastics, lacquer, paint, glue, industrial processes and foam fillers. Relative abundance of OPs in fine and coarse PM differs amongst OP congeners and concerning seasons, with these variations attributed to different mechanisms of mass transfer such as volatilization, condensation and abrasions. Moreover, triphenylphosphine oxide (TPPO) has been reported in outdoor PMs. This is the first study on the occurrence of OPs in atmospheric fine and coarse PM and their seasonal variation from Pakistan and China.