ALJB is a producer of various kinds of marine products located in the Lampulo fishing port of Banda Aceh, Indonesia. This factory was founded in 2014, has a land area of 40,000 m2 with the largest cold storage capacity in Aceh, namely 2,000 tons and an ice factory with a production capacity of 4,000 sticks of ice per day. The products produced are frozen and packaged fresh fish. The main concepts of PT Aceh Lampulo Jaya Bahari are "freshness", "hygienic", and "quality". Based on field surveys and observations, despite implementing a quality management system, defects and errors were still found that were unavoidable. This research was conducted to find the biggest problem that resulted in defects in the product and to find the root of the problem so that improvements can be made. Pareto diagrams are used to see what the biggest problem that causes defects is. From the data on the number of productions for 1 year, there are 6530 units of reject products, including 120 units of leaking plastic, 79 units of dehydration, 114 units of discoloration and 56 units of product appearance with a total damage of 368 units, therefore it is very important to improve the quality of tuna cube fish products. both in terms of color, shape and packaging. After that, the largest number of defects was obtained, then the root cause of the defects in tuna fish was searched using Fault Tree Analysis (FTA).

Keywords : Quality; pareto diagram; Fault Tree Analysis.