Pink oyster mushroom (Pleurotus flabellatus) is one of the oyster mushroom varieties that has a distinctive aroma similar to lingzhi mushroom, pink color, numerous clusters, and a slightly firm texture. The aim of this research was to determine the growth and production stimulation of pink oyster mushrooms (P. flabellatus) through supplementation of CaCO3 from shellfish shells and coconut water. This study utilized a Completely Randomized Design (CRD) arranged in factorial with two factors, consisting of four levels with three replications. The first factor was CaCO3 supplementation from shellfish shells with four levels: K0: 0 gr/baglog, K1: 5 gr CaCO3 from shellfish shells/baglog, K2: 10 gr CaCO3 from shellfish shells/baglog, K3: 15 gr CaCO3 from shellfish shells/baglog. The second factor was coconut water supplementation with four levels: A0: 0 ml/baglog, A1: 20 ml coconut water/baglog, A2: 40 ml coconut water/baglog, A3: 60 ml coconut water/baglog. The results showed significant differences in mycelium growth rate and highly significant differences in pileus number, pileus width, pileus thickness, stalk height, and mushroom fresh weight. Supplementation of 10 gr CaCO3 from shellfish shells/baglog and 40 ml coconut water/baglog showed the best interaction for all parameters.