Background: Atopic dermatitis(AD) that begins in childhood and is the first step of the so-called 'atopic march'. The chromosome 1q21 region has been associated with AD and psoriasis, with a peak in Epidermal Differentiation Complex (EDC) in a region of 2.05 Mb. The aim of this work was to study LELP-1 (late cornified envelope-like proline-rich 1) polymorphism [rs7534334] located within the EDC, in AD and asthma in two European populations: Portugal and Poland. Methods: We studied 110 individuals in the control group and 129 asthmatics in the Portuguese cohort; 100 controls and 45 patients with AD and asthma in the Poland cohort. Written informed consent was obtained from all participating individuals. LELP-1 genotypes were determined by the PCR-RFLP technique. All statistical analyses were carried out using SPSS 21.0 software. Results: The results were considered statistically significant with p<0.05. We found that the CC genotype was more frequent in Poland’s cohort with AD and asthma when compared with controls (p=0.004), (OR: 2.80 [1.34-5.82]; adjusted p=0.006) and the C allele was also a risk factor (OR: 2.40 [1.35-4.28]; adjusted p=0.003) to both diseases in this group. When compared the cohort from Portugal with Poland, there was a trend for TT genotype to be a risk for asthma in the Portuguese cohort (OR=7.49 [0.92-60.91], adjusted p=0.06). C allele was more frequent in the cohort from Poland and T allele, in the cohort from Portugal (p=0.047). Conclusion: These findings demonstrate that genetic variation of skin barrier genes like LELP-1 might contribute to allergic diseases.