This study investigated the association of asthma, allergic rhinitis, and eczema in United Arab Emirates (UAE) schoolchildren with allergic conditions in their parents. A cross-sectional, population-based study among schoolchildren aged 6-14 years was conducted in Al-Ain City, UAE. The field survey was conducted from October 1992 to May 1993. A questionnaire was distributed to 850 UAE government school students from representative, randomly selected schools with a majority of UAE nationals. The student and both or either of the parents were present during the interview. A detailed clinical history of asthma and wheezing in the target children and a history of asthma and allergic rhinitis in their parents and siblings were obtained. It was found that 13.1% of asthmatic children had mothers with asthma (relative risk (RR)=2.67; 95% confidence intervals (CI)=1.65-4.35), and 15.2% had fathers who were asthmatic (RR=2.85; 95% CI=1.81-4.49). This contrasted with 4.4% of nonasthmatic children who had fathers with asthma, and 4.1% who had mothers with asthma. A similar pattern was seen with symptoms of allergic rhinitis when it was found that 34.3% of children who had asthma had mothers with allergic rhinitis (RR:2.74; 95% CI:1.90-3.94). The corresponding figure for fathers was 12.7% (RR:0.92; 95% CI:0.5-1.7). The frequency of either parent of the asthmatic children having allergic rhinitis was 28.6%; for both parents, it was 14.5%,. It was also found that asthmatic children had 12.5% of their fathers, 32.8% of their mothers, 26.4% of either of their parents, and 33.3% of both their parents suffering from allergic rhinitis. Siblings of the asthmatic children were also studied to establish the relationship between allergic conditions in the siblings and asthma in the study sample. It was found that in the asthmatic study population the frequency of siblings having asthma was 31.9%; of those having allergic rhinitis, 21.3%; and of those having eczema, 16.1%. Twenty-nine percent of either of the parents of the children with eczema had the same condition, and the corresponding figure for allergic rhinitis was 36.5%. The prevalence rate of asthma in the schoolchildren studied increased dramatically to 22% when wheeze, asthma, or nocturnal cough were grouped together. When eczema and allergic rhinitis were also considered together along with the above, the rate increased to 31%. The size of the family did not seem to affect the parent/child association of allergic symptoms. Our findings indicate that there is a strong association between respiratory allergies and eczema in parents and in their asthmatic children, thereby indicating a strong genetic basis for the occurrence of asthma in particular and atopy in general.