The nonlinear optical coefficients of ${\mathrm{LiB}}_3{\mathrm{O}}_5$ (LBO), ${\mathrm{CsB}}_3{\mathrm{O}}_5$ (CBO), and ${\mathrm{CsLiB}}_6{\mathrm{O}}_{10}$ (CLBO) crystals have been measured by both the Maker fringe technique and the phase-matching method. With the former technique the coefficients of LBO, CBO, and CLBO crystals have been determined relative to $d_{36}$ (KDP) at the wavelength $1064.2\mathrm{nm}$ . The relative ratios of the $d_{ij}$ coefficients measured by Maker fringe technique have been found to be in good agreement with those deduced by the phase-matching method.