Different seaweed farming trials were perfomed in Tunisia on the agarophyte red alga Gracilaria during the last two decades. However, carrageenophtye seaweeds have never been farmed. Moreover, Tunisia is not a carrageenan producing country from its own seaweeds. This study consists of the first trial aiming at providing information on the effect of initial cutting weights on growth of the red carrageenophyte seaweed Hypnea musciformis cultivated in the open sea , in the North coast of Tunisia (Salammbo- Tunis). Thus, three initial cutting weights (5 g, 10 g and 15 g) were tested. Seaweeds were put in netting pockets tied to three nylon ropes. Each rope consists of 12 netting pockets and fixed to two metallic stakes. Cultivation was performed at 0-1m depth. On the other hand, carrageenan extraction was carried out to assess yield and quality properties (gel strength, gelling and melting temperatures and viscosity) from farmed seaweeds. Results are presented in Table 1. After 45 days of cultivation, the highest weight gain was obtained in cuttings with an initial weight of 5 g. Daily growth rate (DGR) was also obtained in the same plants, while the lowest one was recorded in cuttings with an initial weight of 15 g. As for carrageenan yield, values ranged from 14.33 ± 7.30 % to 19.93± 3.80 % DW, according to the initial cutting weight. Gel strength varied between 70 g.cm-² and 115 g. cm-².Gelling temperature ranged from 19.5°C to 27°C . Melting temperature ranged from 40°C to 47°C. The highest viscosity of carrageenans was recorded from cuttings with an initial weight of 10 g, while the lowest one was obtained from the plants with an initial weight of 5 g .All these results showed that Hypnea musciformis could be a promising seaweed candidate for cultivation and carrageenan extraction in Tunisia. Further investigations are needed to enhance knowledge on farming and carrageenan extraction conditions of H. musciformis.