The main goal of this paper was to set up guidelines to standartize the procedure of developing embrio-larval toxicity tests using the native Brazilian mussel Perna perna (Mollusca: Mytilidae). In vitro spawning tests were carried out using adult organisms in order to obtain healthy gametes. Embryos development response caused by variation of temperature, salinity and incubation time was investigated in order to determine the end point and ideal parameter settings to develop toxicity assays. Different data sets treatments were carried out using the reference chemical Dodecyl Sodium Sulfate (DSS) in acute (Effective Concentration – EC50) and chronic (No-Observed- Effect Concentration – NOEC) tests. The EC50 for DSS ranged from 0,45 (20 °C/48 h) to 1,88 mg/l (25 °C/24 h), while NOEC values ranged from 0,185 mg/l (20 °C/48 h) to 0,75 mg/l (25 °C/24 h). Comparing the Perna perna embrios response with those from other test organisms, it was observed that this species exhibited a high sensibility, where a more accurate response were found in chronic treatments.