Glaucoma is a serious vision threatening disease. In the course of management surgical interference may be needed (either as a primary decision or as a final solution after failure of all other approaches). Filtering bleb surgeries are still the most practically applied surgeries; yet many operative and post operative complications could arise and alter the aimed goal in controlling the intra-ocular pressure. Careful preoperative evaluation of the possible risk factors is essential for proper and accurate decision regarding the surgical approach and the possible expected difficulties and complications. Postoperative follow-up is the most important step in the course of management of glaucoma surgeries. Some complications may arise immediately postoperative and others may arise as far as ten years or even more. Understanding the nature of the bleb and pathology of the complications is essential for proper intervention regarding the time and the technique of the approach. Recently there are new techniques that may help in situations of glaucoma filtering bleb failures or to replace them as a primary choice but more studies and follow-up are needed to evaluate them.