The socio-demographic characteristics and prevalence of parasitic infection of 117 (96 males and 21 females) construction site workers were investigated by means of questionnaires and stool examinations. The age characteristics of the individuals investigated varied widely from 15-60 years with a high percentage in the 21-30 years age range, no sex differences were discovered. Most of the workers received primary education even though some of them did not complete it. The percentage of illiteracy in females was quite high (9.5%) compared with males (2.1%). About 60% and 20% of these construction site workers migrated from the northeastern and northern regions of Thailand, respectively. 79.3% of male and 94.7% of female workers were found to be infected with parasites. Hookworm and Opisthorchis were predominant parasites.