The present invention relates to erlotinib hydrochloride Form A that includes no detectable erlotinib hydrochloride Form B； as determined by X-ray powder diffraction analysis that includes a differentiation resolution and a 2-theta scan region that enables detection of the absence, or presence, of a characteristic 2-theta peak of erlotinib hydrochloride Form B in the region of 6.0 to 6.4 degrees 2-theta. There is also provided a pharmaceutical composition comprising the same. Furthermore, a composition according to the invention can be further characterized by a stability profile whereby on storage at (i) a temperature of at least about 23oC, (ii) a relative humidity of at least about 55 pcnt , and (iii) for a period of at least about 6 months, no erlotinib hydrochloride Form B is detectable by X-ray powder diffraction analysis.
