The method of determining the ratio between lattice parameter and electron wavelength from Kikuchi‐line intersections with an accuracy about 0.1% which was described by Høier [Acta Cryst. (1969). A25, 516–518] for cubic crystals, is extended to crystals with any lower symmetry. A computer program using a least‐squares refinement has been developed and applied to the determination of unknown lattice parameters in an orthorhombic olivine and a triclinic feldspar crystal. A combination of energy‐dispersive X‐ray analysis and Kikuchi‐line intersection measurements can in many cases be utilized to increase the accuracy in the determination of the lattice parameters. For the feldspars such a combination of measurements can be used to determine the distribution of the Al and Si atoms in the tetrahedral positions of t