A direct measure of the effect of porosity on powder diffraction intensities can be obtained by measuring the ratio of the x‐ray scattering from a porous, amorphous material vs its nonporous counterpart. The amorphous specimen eliminates the effects of extinction and preferred orientation inherent in diffraction from crystalline samples. Measurements on glass powders of controlled particle size vs solid specimens were used to obtain porosity corrections for scattering angles 10°<&thgr;<80° and for particle sizes in the range &mgr;t=1.0 to &mgr;t=3.2. With particles of the largest values of &mgr;tthe error can be as great as 30% for &thgr;≈30°. For a given specimen the correction approaches zero as &thgr;→90° and also gets smaller as &thgr;→0°. For specimens of about 50% relative density the maximum correction is approximately (10×&mgr;t)%. Extrapolating to particles with attenuation factors of only 10% (&mgr;t=0.1) corrections as large as 1% in a powder integrated intensity measurement may be necessary.