unmanned aerial vehicles (uavs) are becoming ubiquitous due to their potential benefits in many civilian and military applications. uavs are designed to accomplish complex tasks safely and effectively, such as search and rescue missions, package delivery, building inspections, film making...etc. the attitude controller is one of the most important and fundamental components that allows the uav to balance itself in the air. in this thesis, a px4-based quadrotor experimental platform has been built and used to test the attitude control algorithms. matlab/simulink r2021a with the uav toolbox support package for px4 autopilots is used to program the control algorithms. a nonlinear attitude estimator and three pid-type attitude controllers have been successfully implemented on the quadrotor. a discussion about the performance of the obtained experimental results for the three different attitude control schemes is provided.