Technology in ultrasonic inspection of polyethylene heat fused joints is rapidly improving. Subtle flaws that could not be detected previously can now be found. Sophisticated methods of destructively testing the fusions appear to confirm these ultrasonic evaluations. Further study could reveal the possibility of predicting long term fusion joint reliability using state-of-the-art ultrasonics. It has been proven that the use of ultrasonic testing of fusion joints in the field and for requalification can greatly improve the quality of workmanship.