The life cycle of Dermatophagoides pteronyssinus was studied at 25 °C and 80% relative humidity. Observation was made on freshly laid eggs until they develop into adults and periods between different stages were recorded. The eggs required an average 11.26 days to develop into adults. The ranges of life longevity of mated males and females were 18-64 days and 20-54 days, respectively. The conditions used in the rearing experiments may be considered optimal for maintaining culture of D. pteronyssinus. © Acarina 2009.