We performed a clinico-pathological study on cases with early gallbladder carcinoma to elucidate its morphological characteristics. Thirty cases (33 lesions) were included, invasion was confined to the mucosa in 24 of these cases and involvement of both the mucosa and muscularis propria was seen in 6 cases. The results are as follows: 1) In all cases with I p-type cancer, the depth of invasion was limited to the mucosa. 2) In I s cases in which the tumor had a broad base, 10mm in size or less, the depth of invasion was up to the muscularis propria. 3) In cases with II a-type carcinoma in which the base was less than 15mm in size, no involvement of the subserosa was observed. In conclusion, it is suggested that with lesions diagnosed by imaging modalities as I p-type cancers, broad-based tumors with a base of 10mm or less, or II a-like lesions with a base less than 15mm, there is a high probability that the depth of invasion is limited to the mucosa or up to the muscularis propria.