The study aims at estimating the heavy metals and chemical constituents in the marine colonial ascidian Didemnum psammathodes. Accumulation of heavy metals like copper, cadmium, lead, arsenic, zinc and mercury were determined. Analysis of the heavy metal in the selected animal sample was performed by atomic absorption spectrophotometer (AAS). Measurements were made using a hollow electron discharge lamp (EDL) for copper, cadmium, lead, arsenic, zinc and mercury at wavelengths of 220.62 nm, 228.80 nm, 283.31 nm, 193.70 nm, 240 nm and 253.7 nm respectively. Chemical constituents were analysed by spectrophotometric methods. This study confirms that the risk of heavy metals contamination in the ascidian appears low when compare to high amount of phenols and flavonoids..