This research has attempted to examine the influence of the firm's internal and external environmental factors upon its adoption behaviour of HRIS applications. To achieve the study objectives, and to conduct the research in a systematic approach, a conceptual framework was developed. The conceptual framework ties together the major factors proposed to influence the firm's adoption of HRIS applications. The key factors were presented under two broad dimensions, i.e., internal and external. The data for this research were collected through structured-directed interviews with 236 respondents. The target respondents were the shareholdings companies in Jordan, and the key respondent approach was employed. The primary date has been analysed by a variety of multivariate statistical techniques including; discriminant function analysis, the Jacknife and split-half methods for validating the DFA functions; the chi-square test, the univariate F-ratio test; McNemar test, and the t-test. The result provides empirical evidence that the integration approach of the firm's internal environmental and its external environmental measures give better explanation of the prediction of adoption of HRIS behaviour (i.e., classification of adoption group membership).