Stem cell has the ability of self renewal or differentiation into more specialized cells. Embryo quality is detected by microscopic assessment of cell number, fragmentation & others. Aim of our study: detect effect of stem cell application on poor quality embryos, either improving or not. Methodology: 50 poor quality embryos divided into 2 equal groups (cases & controls). We added stem cell supernatant on each embryo of the cases After 3 days: improvement of most of the cases, but worsening of most of the controls. Conclusion: stem cells can improve poor quality embryos but genetic diagnosis is required.