This study was aimed to analyze the disease incidence and prevalence development of Kappaphycus alvarezii from green and brown varieties. This study used a completely randomized design experimental method with two treatments and four replications. Seaweeds were reared with a longline culture method. The initial weight of seaweeds from each replication unit was 2.70 kg. Incidence and prevalence were observed every day until the 42-th day of culture period. All data obtained were analyzed with an independent t-test. The results showed that there were six incidents of pests and disease attack/infection on two seaweed varieties, namely: (1) Rabbitfish Siganus sp., (2) Epiphytic Filamentous Algae (EFA), (3) Green filamentous algae (Chaetomorpha sp.), (4) Brown seaweeds Sargassum sp., (5) Ice-ice disease, and (6) Fusarium sp. mold. Each attack/infection from six pests and disease was insignificantly different (p>0.05) on both seaweed varieties during observation. The weight gain of green variety slightly increased at 0.15±1.48kg, but the value was lower than brown variety at 0.73±0.39 kg. Therefore, both varieties of K. Alvarezii can be cultured at the same planting period. Pest and disease attacks can be reduced by moving the seaweed to other safer locations.