Medium of instruction controversy in Nigeria has led, among other things, to focusing attention on the use of mother-tongue. Many of the cities and urban areas are multi-ethnic and as a result, the major means of communication is Pidgin which is an adulterated form of English Language. Suggestions, based on mere conjectures rather than empirical evidence, have been made for the use of Pidgin for teaching science to primary and secondary school students in such cities. There is the need to investigate if empirical evidence will support the suggestions. This study, therefore, sought to investigate the efficacy of Pidgin, as a medium of communication, for teaching Biology. One hundred and twenty three (65 boys, 58 girls) senior secondary one (grade 10) students participated in this experiment. Using a non-equivalent control group design, the experimental group was taught using Pidgin as the medium of instruction while the control group was taught using English Language. Analysis of data using a fixed ANOVA model support the stand that use of Pidgin is significantly more effective than English Language in enhancing learning in biology.