A new compound, namely pefloxancindium tetrabromidozincateC(17)H(22)FN(3)O (3) (2+) center dot ZnBr (4) (2+) where C17H20FN3O3 is 1-ethyl-N-methyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-methyl-1-piperazinyl)-3-quinoline carboxylic acid (PefH, pefloxacin), has been synthesized and its crystal and molecular structure has been solved. It contains PefH (3) (2+) and ZnBr (4) (2-) ions. The latter is a slightly distorted tetrahedron. The supramolecular architecture of a crystal has been analyzed.