Doubly Cabibbo-suppressed (DCS) nonleptonic weak decays of antitriplet charmed baryons are studied systematically in this work. The factorizable and nonfactorizable contributions can be classified explicitly in the topological-diagram approach and tr
eated separately. In particular, the evaluation of nonfactorizable terms is based on the pole model in conjunction with current algebra. All three types of relevant non-perturbative parameters contributing factorizable and nonfactorizable terms are estimated in the MIT bag model. Branching fractions of all the DCS decays are predicted to be of order $10^{-4}sim 10^{-6}$. In particular, we find that the three modes $Xi_c^+to Sigma^+ K^0, Sigma^0 K^+$ and $Xi_c^0to Sigma^- K^+$ are as large as $(1sim 2)times 10^{-4}$, which are the most promising DCS channels to be measured. We also point out that the two DCS modes $Xi_c^+to Sigma^+ K^0$ and $Xi_c^0to Sigma^0 K^0$ are possible to be distinguished from $Xi_c^+to Sigma^+ K_S$ and $Xi_c^0to Sigma^0 K_S$. The decay asymmetries for all the channels with a kaon in their final states are found to be large in magnitude and negative in sign.
