This article has three main objectives: i) to describe the use patterns of electronic and traditional resources in Portuguese academic libraries; ii) to estimate the value of the Portuguese electronic scientific information consortium b-on by using two alternative valuation methodologies; iii) to relate the use patterns with the valuation of b-on. We estimate the value of the Portuguese electronic scientific information consortium b-on by using two alternative evaluation methodologies: a) the value of the time saved by using this electronic resource; and b) the contingent valuation method to estimate how much the user is willing to pay for the service. Our results show wide differences in use patterns, with professors, researchers and PhD students having a more intense use of digital library services than undergraduate and masters students. Moreover, the benefit-cost ratios computed using the two valuation techniques indicate that the value of the electronic scientific information consortium b-on is well above its costs. Finally, the study shows that the valuation of b-on is higher for the user groups with higher percentage use of digital services. (Contains 6 tables, 1 figure and 4 notes.)