The fruit fly drosophila melanogaster serves as the classic model for the demonstration of the basic phenomena of genetics. With its easily recognizable genetic markers it is also ideally suited as a test organism for screening newly developed substances for toxicity and mutagenicity. The practical course manual on drosophila includes all experiments on formal genetics which can be carried out without expensive equipment. The experiments are described in enough details that teachers and students with little previous experience in drosophila techniques can complete them successfully. A results and answers section helps students to control their experiments and guides them through scientific reasoning. Routine laboratory procedures can be established following this manual and it serves as a prerequisite to perform more sophisticated experiments including techniques of molecular genetics.