1 Abstract. The formulation of the problem in this research is how to develop a valid molecular genetics practicum guide with the aim of testing the validity of the practicum guide in molecular genetics courses for undergraduate biology study program students. This type of research is Research and Development (R&D) with the ADDIE development model which consists of five stages, namely analysis, design, development, implementation and evaluation. The instrument used is a validation sheet filled out by a validator expert. Data was collected through analysis of validation sheets that had been filled in by expert validators and analyzed descriptively in order to obtain data in the form of a validity score. The results showed that practicum guides had an average validity score in the range of 4.5 ≤ Va = 5, in this case it met the very valid criteria. Keywords: ADDIE development model, practicum guide, molecular genetics Aulya Novira Universitas Negeri Makassar Indonesia Oslan Jumadi Universitas Negeri Makassar Indonesia Hartono Universitas Negeri Makassar Indonesia Irma Suryani Universitas Negeri Makassar Indonesia Biology Teaching and Learning p-ISSN 2621 – 5527 e-ISSN 2621 – 5535 Validity of Practicum Guide in Molecular Genetics Course for Bachelor's Student of Biology Study Program of Mathematic and Science Faculty in Universitas Negeri Makassar Aulya Novira Oslan Jumadi Hartono Irma Suryani Introduction The development of biology on average comes from a concept of genetics, in other words, genetics is a biological science that covers all life sciences. Genetics is not just about the inheritance of traits but a branch of biology that studies genetic material, its structure, expression, and presence in populations and their engineering (Corebima, 2009). Genetics can also be said to be a study that discusses or studies genes and all aspects of them. Broadly speaking, the branches of genetics include; cell genetics, molecular genetics, developmental genetics, and quantitative and population genetics. Genetics is an example of a course that must be followed and studied by learners in pursuing higher education, especially in the biology department (Lauren, et al., 2016). Molecular genetics is a compulsory subject of the Bachelor's Degree Study Program of the Department of Biology, Mathematics and Science Faculty, Universitas Negeri Makassar which weighs 3 credits. The general purpose of this course is for students to master the theory of Biotechnology obtained in class and to prove the theory obtained in the laboratory. The theoretical lecture process is carried out with a cooperative learning approach and practicum in the laboratory is carried out through experiments. The problem obtained by researchers when making observations is that there is no molecular genetics practicum guide because there is no practicum guide during the molecular genetics lecture process. The result arises is that students have not been able to prove the concepts/theories they have obtained directly in the laboratory, so their mastery of theories about molecular genetics courses is very lacking. The existence of practicum activities is important in learning biotechnology because it can help improve student skills both in the fields of science and education. In line with Abu, et al. (2019) that one of the skills that must be possessed by biology graduates is expertise and skills in practicum activities. Practicum