Interfaces development process conducted with no attendance to usability requirements leads to a poor performance and to a reduction in the quality of user interaction with a software. From this point was intented to investigate wich was the main factores that colaborate for the user satisfaction. It was assumed that the satisfaction level is improved when the satisfaction is considered by a approach that puts value on the product experience of use. Two interfaces for information retrieval on university libraries catalog was evaluated. The main goal was to colaborate to the improvement of the user interaction with web based bibliographical information retrieval systems. The secondary goals was: select two interfaces to be evaluated; to apply questionaire for user satisfaction; to conduct qualitative interviews; to develop a semi- functional prototype; to to evaluate the prototype by focus group and user satistaction questionaire; to compile recommendations for bibliographical information retrieval systems interface of on-line libraries. The results show that the interface especifications configured on the prototype has improved the user satisfaction. The results also show that the three usability aspects - effectiveness, efficiency and satisfaction - was achieved.