We have conducted spectral line survey observations in the 3 mm band toward two low-metallicity dwarf galaxies the Large Magellanic Cloud (LMC) and IC10 to reveal their chemical compositions. For the LMC, we have observed seven clouds, which have different star-formation activities; two are quiescent molecular clouds without infrared point sources, three are those associated with high-mass star formation, and two are active star-forming regions with the extended HII regions. Spectral lines of fundamental species such as CCH, HCN, HCO+, HNC, CS, and SO are detected in addition to those of CO and 13CO, while CH3OH is not detected in any sources. The molecular-cloud scale chemical composition of the seven clouds is found to be all similar regardless of different star formation activities, and hence, it represents the chemical composition characteristic to the LMC without significant influences by star formation activities. Following the observation toward the LMC, we have conducted another observation toward IC10. As a result, the lines of CCH, HCN, HCO+, HNC, CS, SO, 13CO, and CO are detected, while c-C3H2, N2H+, CH3OH, C18O, and CN lines are not detected. The spectral intensity pattern of IC10 is found to be similar to those observed toward the seven clouds in the LMC. Compared to chemical compositions of Galactic sources, the characteristic features are (1) deficient N-bearing molecules, (2) abundant CCH, and (3) deficient CH3OH. Feature (1) is due to a lower elemental abundance of nitrogen in the LMC and IC10, whereas features (2) and (3) seem to originate from extended photodissociation regions in cloud peripheries due to a lower abundance of dust grains in the low-metallicity condition.