Globally, the number of new cases of leukemia annually was ~13 per 100,000 men and women. The number of deaths annually was 7 per 100,000 men and women. These rates are age-adjusted and based on 2008-2012 cases and deaths. Various therapeutic options are available against Chronic lymphocytic leukemia (CLL) but each has its own limitations and they do harm to healthy cells which is why there is a trend shifting toward the use of natural products. Among various available sources of natural bioactive compounds, marine sponges are attracting the attention of the scientific community due to the safety and efficacy of the compounds isolated from them. Such compounds are highly diverse and some have shown the ability to interact with different molecular targets implicated in carcinogenesis. In this study, two compounds purified from Aplysilla rosea, a South Australian marine sponge were screened for their anticancer activities against a human chronic lymphocytic Leukemia cell line (JVM-3) and a human lymphoblastoid cell line of non-cancer origin (WIL2-NS). To screen the cytotoxicity activities of these compounds, the MTT assay was used, which detects a colourimetric endpoint (OD 520 nM) to monitor survival in 96-well microplates. The cell lines were treated for 24h with five concentrations ranging from 167 µg/ml to 0.0167 µg/ml. This enabled a concentration curve to be constructed for the effect of each of the 2 compounds on cell killing. This will be the first report of a screen of the anticancer activities of compounds purified from the Aplysilla rosea sponge of South Australia.