Celiac disease (CD) or gluten-sensitive enteropathy is strongly associated with HLA-DQ alleles; more than 95% of patients are DQB1*02. However, the uniform association with HLA-DQ alleles does not explain the clinical heterogeneity, especially the wide range in the age of onset of CD. We asked whether the age of onset of CD is also influenced by class I genes of the human MHC. We performed HLA typing in three groups of patients suffering from CD. The age of onset in the first group (N = 200) was before 15 years of age, in the second group (N = 62) between 15 and 40 years, in the third group (N = 59) after 40 years. We observed a statistically significant increase in the frequencies of HLA-B8 and Cw7 with increasing age of onset. In conclusion, we conclude that distinct alleles from the class I region of the human MHC might lead to late onset of CD. In particular, relatives of CD patients with the disease-prone HLA class I alleles HLA-B8 and Cw7 should be followed up carefully for late onset of CD.