This article presents the findings obtained from a palynological analysis of ashes contained in mortuary urns excavated in a necropolis in south Sardinia, Cagliari, Italy that dates back to the Roman Imperial age (1st century BC–4th century AD). The pollen content in the urns is mainly referable to the natural environment of the burning site and suggests that local vegetation was from a clearing characterised by dry saline soils. Data suggest that burning rituals were carried out near wet and saline environments, since chenopods (Salsola and Arthrocnemum) are constant elements in the mortuary ashes examined. Cremations would have occurred far away from the settlement areas, probably in local places in the marshy area located to the west and east of the necropolis and the Roman urban settlement. In general, the pollen content of the flowering plants retrieved points to the season when the funeral ceremonies occurred. The presence of charred conifer pollen grains, and the absence of suitable pieces of charred wood, suggests that the funeral pyres were probably built using conifer wood. Through this research, a complementary methodology of investigation in the field of environmental archaeology was tested.