This research reports on implementing the integrated laboratory work to achieve effective learning in the biochemistry course. The integrated laboratory work includes three stages: pre-laboratory, lab work, and post-laboratory. In other words, the three stages include planning, implementing, and evaluating investigation activities in the laboratory. The research design used was a posttest control group design consisting of a control and an experimental group. There were 67 students as respondents, who were divided into control (N = 33) and experimental (N = 34) groups. Practical skills were measured using an assessment rubric with the involvement of the observer. The categories of practical skills measured were procedural skills, observation skills, interpretation skills, and reporting skills. Attitude toward biochemistry was measured using a questionnaire with five Likert scales. The indicators of attitudes toward biochemistry used were liking for a biochemistry theory lesson, liking for biochemistry laboratory work, evaluative beliefs about biochemistry, and behavioral tendencies to learn biochemistry. The influence of the implementation of the integrated laboratory work on the students' practical skills and attitudes toward biochemistry was analyzed using MANOVA. The research result shows that implementing the integrated laboratory work improves students' average scores in practical skills and attitudes toward biochemistry. All the practical skills and attitudes categories in the experimental group have a higher score than those in the control group. The reason is that the work of the integrated laboratory can prepare students to conduct better investigations in biochemistry laboratory work.