Similarities between Mitochondria and Chloroplasts:

1. Mitochondria and Chloroplasts may have existed as independent organism, which during evolution developed a symbiotic relationship with plant and animal cells.
2. Both are semi-autononus organelles as both contain DNA, RNA and ribosomes.
3. The symbiont hypothesis suggest that there are many similarities  between prokaryotes on one hand, and mitochondria and chloroplasts on the other, e.g. the presence of circular DNA not associated with histones and 70 S ribosomes.