The purpose of this study was to analyse the effect of national cultural differences on the response rate, obtained in questionnaire based epidemiological studies on allergy and asthma, performed in Sweden (DBH) and Bulgaria (ALLHOME). The two studies used one and the same methodology, but the obtained response rate was different: 78.8% in DBH and 34.5% in ALLHOME. The differences in the obtained response rate and the reasons for these differences were analyzed on the basis of the Hofstede’s cultural dimensions’ indexes, which clearly show the distinction in the national cultural behaviour of people in Sweden and Bulgaria. It was found that national culture could strongly influence the response behaviour of people in epidemiological studies and Hofstede’s indexes can be useful tool when designing and performing epidemiological studies, and in particular - questionnaire surveys.