A series of taxoids, isolated from the stems of Taxus cuspidata var. nana, showing a cell growth inhibitory activity, were investigated for their 3D QSAR by using the comparative molecular field (CoMFA) analysis. The results indicated a strong correlation between the P388 cell growth inhibitory activity of these taxoids and the steric and electrostatic factors which modulate their biological activity, and accounted for the potent activities of the taxoids with the N-acylphenylisoserine derivatives at C-13 and the weak activities of those without this kind of ester group. It was also suggested that the substituent at C-2 is not a requisite for the biological activity: smaller substituent seemed to favor the biological activity. © 1997 Published by Elsevier Science Ltd.