The ability to maintain water continuity in the xylem under a low water potential (low vulnerability of xylem to dysfunction) is considered to be responsible for adaptation to drought in cashew. The effect of shading on the xylem vulnerability of cashew seedlings was evaluated since the plants are grown under shading at the nursery stage. A strain with a resistant xylem (A3-1) and two strains with a vulnerable xylem (G-85 and Wonogiri-2) were grown in an open field and under shading for four months, and then the xylem vulnerability was determined. In A3-1, the applied pressure that induced a 50% loss of hydraulic conductivity (P₅₀), which was the indicator of xylem vulnerability, was 1.55 MPa in the open field and A3-1 was found to be less vulnerable than G-85 and Wonogiri-2 in which the P₅₀ value was ca. 1.2 MPa. The vulnerability increased under shading in A3-1, whereas it was not affected by shading in G-85 and Wonogiri-2, resulting in the absence of difference in vulnerability among the strains under shading. Stem length/diameter ratio increased in the three strains under shading, indicating the existence of spindly growth. The degree of spindly growth was largest in A3-1 and the vessel diameter increased only in A3-1. It was considered that the fragile vessel wall and the increase in the vessel diameter associated with spindly growth was responsible for the increase in the vulnerability under shading in A3-1. These results suggested that it would be important to grow the seedlings of A3-1 which displayed a resistant xylem under shading without spindly growth.