The development of web search engines has provided an alternative for undergraduates to access the needed information for their research activities without utilising library resources, especially reference sources. This avenue created by web search engines is viewed by some as detrimental, as undergraduates now display apathy towards the use of reference sources, even though web search engines have their own limitations. Based on this, the main objective of this study was therefore to examine undergraduates’ preference between web search engines and reference sources for research activities. Descriptive survey design was adopted for the study and the study population consisted of all 12,173 regular undergraduates in University of Ibadan (UI) and 2,388 in Redeemer’s University Ede Osun State, Nigeria (RUN). Multistage random sampling technique was used to select the sample size of 386 and the questionnaire was research instrument. Findings showed that most of the undergraduates in UI 195 (97.0%) and RUN 130 (92.9%) indicated that Google was their most used search engine. While, 179 (89.1%) and 124 (81.4%) of undergraduates in UI and RUN pointed out that dictionaries were the most used reference sources. Results also showed that majority of undergraduates in UI 161 (83.1%) and 111 (79.3%) in RUN indicated their preference for web search engines for research activities as against reference sources. Despite the undergraduates’ preference, the reference sources still have the potential of providing answers to any type of users’ queries. It was therefore recommended that the reference librarians should provide the needed user education on the various types of information contained in the reference sources during library orientation program. The management of the university libraries should also ensure the availability and accessibility of current and adequate reference sources.