Microalgae are aquatic organisms having the capability of absorbing heavy metals. The objective of this study was to analyze the response of microalgae species Synechococcus sp. to different concentrations of a heavy metal Fe and its ability to absorb Fe. The microalgae used in this study was isolated from a pond in coal mined land. This experiment was conducted using a completely randomized design with five treatments and three replications. The microalgae was grown in one liter of BG 11 medium, with Fe concentrations of 0.56 mg/L, 1 mg/L, 1.8 mg/L, 3.2 mg/L, and 5.6 mg/L. The microalgae was grown for 14 days and the growth pattern was analyzed. The heavy metal analysis was done using Inductively Coupled Plasma. The numbers of microalgae cells after 14 days of culture were 620 cell/mL, 733 cell/mL, 827 cell/mL,548.20 cell/mL, and 422.12 cell/mL at Fe concentrations of 0.56 mg/L, 1 mg/L, 1.8 mg/L, 3.2 mg/L, and 5.6 mg/L respectively. The concentrations of heavy metal in the medium at the end of experiment were 0.315 mg/L, 0.500 mg/L, 0.322 mg/L, 0.630 mg/L, and 1.146 mg/L, respectively declining from the initial concentrations of 0.56 mg/L, 1 mg/L, 1.8 mg/L, 3.2 mg/L, and 5.6 mg/L. The decline of Fe concentration in the medium at the end of experiment showed that Synechococcus sp. had the capability of absorbing heavy metals from its environment. Keywords: concentration, culture media, heavy metal, microalgae, response