The ecotoxicological characterization of sewage sludge takes into account the additive, antagonistic and synergistic effects that occur as a result of multi-chemical interactions. Such an evaluation therefore is essential to complement the chemical analysis that, although required by law, is clearly insufficient. Using a tiered approach in the toxic evaluation of sewage sludge allows for characterization of toxicity in a timely manner. According to the literature, reproduction tests with Folsomia candida are suitable tools for the toxic assessment of organic sludges. Therefore, the inclusion of Collembola avoidance tests at a screening level (low tier), and acting as a trigger for longer-period tests (high tier; e.g. reproduction test), may provide a successful strategy, and may complement the currently proposed test battery. To evaluate the use of both avoidance and reproduction tests with collembolans in such a tiered approach, three sewage sludges (urban, olive and electroplating industries) were mixed in with a field-collected soil at different concentrations. Avoidance and reproduction tests were performed with the soil-sludge mixtures after 0, 4 and 12 weeks of incubation. The tests detected no toxicity in soil-sludge mixtures of urban and olive sludges at any incubation period. Mixtures with sludge from the electroplating industry induced toxicity only in the avoidance tests with freshly prepared and 4-week incubated samples. These results demonstrate the ability of Collembola avoidance tests to assess sewage sludge toxicity over time and its potential for hazardous sludge characterization at low tier levels.