This study investigated effects of unguided use of the internet on undergraduates’ reading and writing skills in English. The study premised on Krashen’s monitor theory that human beings learn language without instruction or feedback on error but with motivation. Aresearcher designed questionnaire was administered to ascertain undergraduates’ reasons for using the internet. Two hundred undergraduates of the faculty of arts were randomly selected from two private and two federal universities in South West Nigeria. Their research projects constituted the data for the study. The projects were subjected to Turnitin to assess originality. Results revealed that students plagiarised verbatim from the internet and other texts as shown by Turnitin. Responses to the questionnaire revealed that students used the internet mostly for social and not for learning purposes. It was recommended that teachers and students need proper orientation on the correct use and management of information from the internet for academic purposes.