Stability studies of some novel dual action fluoroquinolonyl-3′ ′ ′ ′ ′-penicillin amides (1a-e) in aqueous DMF (1:1) solution has been carried out in presence of Cu (ic) or Hg (ic) ions and their degradation rate was monitored by UV/Vis spectrophotometric method. The results thus obtained indicate that ciprofloxacin moiety offered greater stability to the ß-lactam moiety of the hybrid (1d or 1e) than norfloxacin (1a or 1b) in the presence of heavy metal ion degradation; whereas the degradation pattern of ß-lactam moiety in the hybrids under investigation (1a-e) was found to be in agreement with the previously reported heavy metal ion degradation profile of the penicillins.