Cadmium (Cd) bioaccumulation in the wheat (Triticum aestivum L.) and rice (Oryza sativa L.) and the Cd translocation into grains have become a vital global environmental constraint for food security. Cadmium shows higher risk than other heavy metals owing to its toxic effects on plants, animals, and humans. Thus, the present research work was conducted to evaluate the Cd bio-availability, bioaccumulation and toxicity to the plants grown in aged contaminated soil amended with various levels of biochar (BC) either applied alone or under the salt and drought stress. For the achievement of these goals sequential pot experimental studies were carried out in the seasons of wheat and rice cropping system in Cd-contaminated soil under ambient conditions amended with different levels of BC (0, 1.5, 3.0 and 5% w/w) produced from rice straw. First, wheat was sown in the BC-amended soil and divided into three parts such as only BC applied in Cd-contaminated soil, BC applied in the same soil under salt stress (0 mM, 25 mM and 50 mM), and BC under drought stress; well-watered control (70% of soil water holding capacity, WHC), mild drought (MD, 50% of WHC), and severe drought (SD, 35% of soil WHC). Plants were harvested at physiological maturity (130 days of germination). Result showed that BC supply increased the growth, photosynthesis, dry weights, mineral nutrients as well as antioxidant enzymes whereas reduced the oxidative stress and Cd concentrations in different parts of wheat. The BC supply reduced bioavailable Cd in the soil whereas increased EC and pH of the soil than control treatment. However, higher rate of BC (5.0%) was not affective under higher salt stress (50 mM NaCl) where reduction in plant growth and photosynthesis was observed. Second, rice was sown in the same soil without further amendment of BC and salt whereas drought stress was applied to 35-d-old plants as follows; well-watered control (1-2 cm water layer on soil), MD, 50% of WHC), and SD, 35% of soil WHC) for an additional 35 days. All plants were harvested after 70 days of growth and analyzed for various physiological and biochemical parameters. Biochar supply increased plant height, biomass and photosynthesis whereas reduced oxidative stress and Cd contents in plants which confirmed the residual effects of BC in enhancing plant growth and reducing Cd uptake by plants. Continuous flooding plus BC application was the most effective in reducing Cd concentration in rice than MD and SD. However, plant growth and photosynthesis were reduced with BC amendments under 50 mM salt stress. The BC application reduced the bioavailable Cd in the soil whereas increased soil pH than control. It can be concluded that BC amendment can be used to reduce Cd contents in plants and also had a significant residual effect on decreasing Cd uptake in latter crop. However, BC levels should be carefully applied in the soils having higher salinity.