In this article, we describe a successful adult living related partial liver transplantation (LRLT) using the left lobe with the left-side caudate lobe (the Spiegel lobe and the left side of the paracaval portion). The size of the donor's left lobe was 29% of the recipient's standard liver volume and did not seem to meet our criteria for adult-to-adult LRLT. However, the donor had a thick left-side caudate lobe. The estimated volume of the left lobe with the left-side caudate lobe was 32%, which met our criteria for the adult recipient. The recipient's CT scan on day 87 after transplantation showed the preserved blood flow and no biliary congestion in the left-side caudate lobe, which suggests maintenance of lobe function. This procedure may be an option for adult-to-adult LRLT in which the donor has a thick left-side caudate lobe.