Using a newly reconfigured magnetooptical instrument, originally constructed for magnetic circular dichroism experiments, it has been shown that the ferrous hemoprotein derivatives ferrocytochrome c (S = 0) and deoxymyoglobin (S = 2) exhibit readily detectable magnetic-field-induced linear dichroism (MLD) signals in the near-ultraviolet-to-visible region. To our knowledge, this is the first time MLD spectra have been reported for metalloprotein samples. The results suggest that MLD exhibits selectivity toward the transition type and chromophore spin which is complementary to that of the corresponding magnetic circular dichroism, Not surprisingly, the band patterns detected in the two magnetooptical spectroscopies are qualitatively different. The second-derivative dispersion associated with the ferrocytochrome c Q-band MLD and the linear variation in signal intensity with the square of the field observed for both non-Kramers hemoprotein derivatives studied under nonsaturating conditions are fully in accord with theoretical predictions. These observations establish unambiguously that an MLD effect has indeed been measured. The magnitudes of the ferrocytochrome c excited-state orbital momenta inferred from a combination of MLD and MCD measurements are substantially lower than those previously estimated by consideration of MCD and absorption data, but are in keeping with the available results of the most detailed theoretical calculations concerning metalloporphyrins, Since many other paramagnetic metalloprotein derivatives and model compounds an anticipated to yield MLD spectra, a broad range of potential applications is envisaged.