This study included two trials, the first trial aimed to evaluate the effect of using varying levels of Posidonia oceanica (PO) as untraditional feed ingredient instead of alfalfa hay in rabbit's diets on growth performance, carcass traits, lipid profile and hematological parameters. The second trial aimed to assess the effect of PO diets on physiological aspects and semen traits of male rabbits. The first trial, forty-eight weaned New Zealand white (NZW) were divided randomly into four comparable groups. First group was fed on basal diet while, the other treatment groups were fed on diets containing 7.5, 15 and 22.5 % of PO, instead of alfalfa hay in rabbit's diets, respectively. Results demonstrated that inclusion of PO in rabbits' diets didn't significantly affect either growth performance or carcass traits. For lipid profile, very-low-density lipoprotein (VLDL) and non-high-density lipoprotein cholesterol (NON-HDL) were significantly affected by dietary treatments. For hematological parameters, there were no significant differences among treatment groups except platelets and MCHC. The second trial, three male rabbits from each group were chosen and fed the same diets of the first trial. At (5-6 months age), some physiological aspects and semen quality were evaluated. No significant differences were observed in rectal temperature, pulse rate, respiration rate and semen quality traits except count and concentration however, they increased with increasing level of PO in diets. Therefore, it could be concluded that rabbits fed on diets containing PO up to 22.5% did not show any detrimental effects on growth performance, carcass traits, lipid profile, hematological parameters and semen quality.