The objective of this investigation was to investigate the content, viscosity, and major functional groups of the native alginates extracted from 4 alginophytes collected from the Red Sea coast of Sudan in order to evaluate the quality of the polymer for potential applications. The content of the polymer ranged from 7.99±2.60% to 19.1±1.62% based on dry weight in the 4 seaweeds. The peak characteristics of the major functional groups of alginates were identified between 3469.70 cm-1 to 451.31 cm-1. These peaks specify the presence of hydroxyl (OH), carbonyl (C=O), and carboxyl (COOH) groups, respectively. The M/G ratios of the alginate extracted from the Sudanese brown macroalgae are ≤ 1 indicating that the proportion of guluronic acid is slightly greater than the mannuronic acid. The alginate with highest viscosity was that of Padina pavonica (Linnaeus) Thivy (190.7±1.14 mPa.s) followed by Dictyota dichotoma (Hudson) J.V.Lamouroux (146.96±1.2 mPa.s), Turbinaria ornata (Turner) J.Agardh (140.1±1.14 mPa.s), and Hormophysa cuneiformis (J.F.Gmelin) P.C.Silva (109±0.6 mPa.s). The values of the parameters of the native alginates extracted from the Sudanese macroalgae are comparatively in conformity with values reported for some species from similar geographical regions. These values indicated that the present biopolymer is of a potential with regard to pharmaceutical and industrial applications.