An inquiry-type laboratory was implemented into the chemistry curriculum in high schools in Israel. The study included development of inquiry-type experiments, assessment tools for a continuous assessment of students' achievements and progress, and a long-term professional development program for teachers who decided to implement the program in their schools. The main goal of the study was to provide students with opportunities to learn in an authentic environment in which they can construct their knowledge regarding chemistry phenomena. In addition, by conducting the experiments students were able to practice inquiry skills such as asking questions, hypothesizing, and suggesting a question for further investigation using an experiment that they planned. The analysis of students' laboratory reports clearly showed that they improved their abilities regarding inquiry learning in the chemistry laboratory.