Abstract This contribution reports for the first time the possibility of using radiolysis to engineer stable efficient nanofluids which exhibit an enhanced thermal conductivity. The validation was confirmed on Ag-H 2 O and Ag-C 2 H 6 O 2 nanofluids fabricated via g-radiolysis within the mild dose range of 0.95 × 10 3 –2.45 × 10 3 Gray. The enhanced thermal conductivity of Ag-H 2 O and Ag-C 2 H 6 O 2 nanofluids, was found to be g-radiations dose dependent. In the latter case of Ag-C 2 H 6 O 2 nanofluid, the relative enhancement in the temperature range of 25–50 °C was found to be 8.89%, 11.54%, 18.69%, 23.57% and 18.45% for D 1  = 0.95 × 10 3 Gray, D 2  = 1.2 × 10 3 Gray, D 3  = 1.54 × 10 3 Gray, D 4  = 1.80 × 10 3 Gray and D 5  = 2.45 × 10 3 Gray respectively. Yet not optimized, an enhancement of the effective thermal conductivity as much as 23.57% relatively to pure C 2 H 6 O 2 was observed in stable Ag-C 2 H 6 O 2 nanofluids. Equivalent results were obtained with Ag-H 2 O.