Temperament of a person is determined by the dominance of a particular Khilt (humour). So, it was hypothesized that variation must exist in humours of persons with different temperament. Blood was considered the most suitable Khilt for assessment. The present study was carried out in the Postgraduate Department of Kulliyat, AKTC, AMU Aligarh, from 2008-2010. For this purpose Damvi and Balghami volunteers were selected randomly between the age group of 18-34 years. The study was conducted on 140 healthy volunteers of either sex. The aim of the study was to compare Hb%, RBC count, serum iron in Damvi (sanguine) as well as Balghami (phlegmatic) temperament, and also analyze any variation in the blood constituents of Damvi and Balghami temperament individuals. The temperament of volunteers were determined on the basis of questionnaire prepared in the light of criteria described in classical Unani literature (Ajnas-eAshra).Cyanmethemoglobin, Neubauer’s chamber and Ferrozine methods were used for assessment of the blood constituents. In our study it was observed that the blood constituents (Hb% t=8.5 p<.001, RBC t=6.4 p<.001, serum iron t=6.1 p<.001) were signifi cantly higher in Damvi as compared to Balghami individuals. Thus, it may be concluded that a relation does exist between various hematological parameters and Mizaj of an individual. It was also established that variation does exist in the Akhlat of different temperament and there was predominance of Khilt Dam in the persons with Damvi temperament. Thus, it may be said that predominance of a particular Khilt necessarily exerts its infl uence in formation of a specifi c and unique temperament