Gas condensates are a group of hydrocarbons that are mostly volatile. Contamination of soil by these compounds can have many negative environmental impacts. Therefore, a research was performed to evaluate the effect of various levels of activated carbon on reducing the toxicity of gas condensate- contaminated soil on shoot and root fresh and dry weight and chlorophyll index of marigold plant. This research was conducted as a factorial experiment in a completely randomized design with 4 levels of soil contamination (0, 5000, 10,000, 20,000 micro-liter gas condensate per kg of soil) and 4 levels of activated carbon (0, 0.5, 1 and 1.5% w / w) with three replications in greenhouse conditions. The results showed that in the gas condensate-contaminated soil, the use of activated carbon at levels of 1 and 1.5% in compared with no activated carbon treatment had significant effect on the most of measured traits of marigold (p<0.05). Application of 1.5% active carbon in soil contaminated with 20000 ?l of gas condensate, increased shoot fresh and dry weight, root fresh weight and chlorophyll index by 58, 49, 55 and 25% respectively, in compared to non-use of active carbon at the same level of contaminant.