The new IMPACT 2002+ life cycle impact assessment (LCIA) methodology proposes a feasible implementation of a combined midpoint/damage approach, linking all types of life cycle inventory (LCI) results via 14 midpoint categories to four damage categories. For IMPACT 2002+, new concepts and methods have been developed, especially for the comparative assessment of human toxicity and ecotoxicity. Human damage factors are calculated for carcinogens and non-carcinogens, employing intake fractions, best estimates of dose-response slope factors, as well as severities. The transfer of contaminants into the human food is no more based on consumption surveys, but accounts for agricultural and livestock production levels. Indoor and outdoor air emissions can be compared and the intermittent character of rainfall is considered. Both human toxicity and ecotoxicity effect factors are based on mean responses rather than on conservative assumptions. Other midpoint categories are adapted from existing characterizing methods (Eco-indicator 99 and CML 2002). All midpoint scores are expressed in units of a reference substance and related to the four damage categories: human health, ecosystem quality, climate change, and resources. Normalization can be performed either at midpoint or at damage level. The IMPACT 2002+ method presently provides characterization factors for almost 1500 different LCI-results, which can be downloaded at http://www.epfl.ch/impact. Keywords: Ecotoxicity; human toxicity; IMPACT 2002+; life cycle impact assessment (LCIA); midpoint/damage approach. The new IMPACT 2002+ LCIA methodology proposes a feasible implementation of the aforementioned combined midpoint/damage-oriented approach. Fig. 1 shows the overall scheme of the IMPACT 2002+ framework, linking all types of LCI results via 14 midpoint categories (human toxicity, respiratory effects, ionizing radiation, ozone layer depletion, photochemical oxidation, aquatic ecotoxicity, terrestrial ecotoxicity, terrestrial acidification/nutrification, aquatic acidification, aquatic eutrophication, land occupation, global warming, non-renewable energy, mineral extraction) to four damage categories (human health, ecosystem quality, climate change, resources). An arrow symbolizes that a relevant impact pathway is known or assumed to exist. Uncertain impact pathways between midpoint and damage levels that are not modeled quantitatively are represented by dotted arrows. In addition to this combined midpoint/damage structure, several scientific challenges had to be tackled, especially in the areas of human toxicological and ecotoxicological impacts. New concepts and methods for the comparative assessment of human toxicity and ecotoxicity were developed for the IMPACT 2002+ methodology. For other categories, methods have been transferred or adapted mainly from the Eco-indicator 99 and the CML 2002 methods. The following Sections of this paper discuss the mainThe new IMPACT 2002+ life cycle impact assessment (LCIA) methodology proposes a feasible implementation of a combined midpoint/damage approach, linking all types of life cycle inventory (LCI) results via 14 midpoint categories to four damage categories. For IMPACT 2002+, new concepts and methods have been developed, especially for the comparative assessment of human toxicity and ecotoxicity. Human damage factors are calculated for carcinogens and non-carcinogens, employing intake fractions, best estimates of dose-response slope factors, as well as severities. The transfer of contaminants into the human food is no more based on consumption surveys, but accounts for agricultural and livestock production levels. Indoor and outdoor air emissions can be compared and the intermittent character of rainfall is considered. Both human toxicity and ecotoxicity effect factors are based on mean responses rather than on conservative assumptions. Other midpoint categories are adapted from existing characterizing methods (Eco-indicator 99 and CML 2002). All midpoint scores are expressed in units of a reference substance and related to the four damage categories: human health, ecosystem quality, climate change, and resources. Normalization can be performed either at midpoint or at damage level. The IMPACT 2002+ method presently provides characterization factors for almost 1500 different LCI-results, which can be downloaded at http://www.epfl.ch/impact. Keywords: Ecotoxicity; human toxicity; IMPACT 2002+; life cycle impact assessment (LCIA); midpoint/damage approach. The new IMPACT 2002+ LCIA methodology proposes a feasible implementation of the aforementioned combined midpoint/damage-oriented approach. Fig. 1 shows the overall scheme of the IMPACT 2002+ framework, linking all types of LCI results via 14 midpoint categories (human toxicity, respiratory effects, ionizing radiation, ozone layer depletion, photochemical oxidation, aquatic ecotoxicity, terrestrial ecotoxicity, terrestrial acidification/nutrification, aquatic acidification, aquatic eutrophication, land occupation, global warming, non-renewable energy, mineral extraction) to four damage categories (human health, ecosystem quality, climate change, resources). An arrow symbolizes that a relevant impact pathway is known or assumed to exist. Uncertain impact pathways between midpoint and damage levels that are not modeled quantitatively are represented by dotted arrows. In addition to this combined midpoint/damage structure, several scientific challenges had to be tackled, especially in the areas of human toxicological and ecotoxicological impacts. New concepts and methods for the comparative assessment of human toxicity and ecotoxicity were developed for the IMPACT 2002+ methodology. For other categories, methods have been transferred or adapted mainly from the Eco-indicator 99 and the CML 2002 methods. The following Sections of this paper discuss the main