Between 1984 and 1990, 75 koalas (Phascolarctos cinereus) from the central northern coast of New South Wales (Australia) were presented for necropsy due to motor vehicle accidents. The koalas consisted of 44 males and 31 females. Fifty one of these were between 2 and 7 yr (39 males and 12 females). The greater proportion of koalas, especially males, were struck by vehicles between June and December. The main injuries detected were head injuries (44), hemoperitoneum (16), limb injuries (16), hemothorax (15) and spinal injuries (7). Nine koalas were not dead at the time of the accident but died later following complications from the trauma. Twelve koalas had evidence of underlying disease at the time of accident. Ten of these had either conjunctivitis, cystitis, prostatitis, periovarian cysts, endometritis or a combination of the diseases. All 10 koalas still had good body condition. It is suggested that healthy young to middle-aged males are particularly prone to vehicular accidents during the mating period. This has implications for the management of local koala populations.