Effective teaching of Biology practical entails the use of specimens. However, in Nigeria, some natural specimens are difficult to obtain when needed, hindering the learning and application of science process skills. Consequently, teachers resort to pictorial representation of specimen and to online prints for Biology practical instructions. Another possible alternative less discussed is the use of synthetic or artificial specimens. The goal of this study, therefore, was to examine the effect of using synthetic and natural specimen on practical skills- process skills acquisition and application in Biology practical in secondary schools. It sought to determine the efficacy of using synthetic specimens to complement or substitute for natural specimens in teaching Biology practical. The study employed the pre-test, post-test, control group, quasi- experimental design. A total of 212 senior secondary school (SS II) Biology students in six selected government-owned high schools in Moba and Ijero Local Government Area of Ekiti state, Nigeria, were randomly selected for the study. The schools were paired and assigned to two experimental groups (using synthetic and natural specimens) and a control group (using conventional drawings). Eight instruments were employed for the study and used at treatment stage. Data collected were analyzed using Analysis of Variance (ANOVA), Analysis of Covariance (ANCOVA) and Multiple Classification Analysis (MCA). The results showed that there was a significant effect of synthetic specimens and natural specimens on the proficiency of the students in basic science process skills acquisition (F = 60.470, P<0.05). However, the mean gain of 3.884 which existed between the two groups showed that natural specimens were slightly more effective than synthetic specimens. The results also showed a significant effect for the use of synthetic specimens on process skills acquisition and applications of Biology concept among the students (F = 74.773, P<0.05). The study concluded that synthetic specimens are equally effective as natural specimens in improving the acquisition and application of basic science process skills of students in Biology.