A minimal extension of the Standard Model (SM) is proposed, where observed left-handed neutrinos obtain naturally small Majorana masses through a one-loop radiative seesaw mechanism. This model has two dark matter candidates: a bosonic and a fermionic particle. It has a simple structure and is verifiable in experiments at the Large Hadron Collider (LHC). In the canonical seesaw mechanism, heavy Majorana neutrinos are added to the SM to generate small neutrino masses. However, these particles are too heavy to be observed. In contrast, the one-loop mechanism involves lighter particles that may be detectable at the LHC. The model introduces a second scalar doublet and three heavy neutral fermion singlets under an exact Z2 symmetry. This symmetry ensures the lightest stable particle (LSP) is either the lighter component of the scalar doublet or the lightest neutrino. The model predicts dark matter candidates, either the lightest neutrino or the lighter scalar particle. The Yukawa interactions and scalar terms allow for the one-loop radiative generation of neutrino masses. The resulting neutrino mass matrix is calculated using the exchange of scalar particles, leading to a seesaw scale reduced by a factor of λ5/16π². Assuming λ5 ~ 10⁻⁴, the seesaw scale is reduced from 10⁹ GeV to ~1 TeV, making it experimentally accessible. The model also predicts observable decays of dark matter particles, allowing for the extraction of Yukawa couplings and verification of the seesaw mechanism. The scalar particles can be produced via SM gauge bosons and their decays can produce neutrinos. The model is suitable for studying lepton family symmetry and can incorporate tribimaximal mixing with tetrahedral symmetry. In conclusion, this minimal extension of the SM provides a framework for realistic neutrino masses and dark matter candidates, with potential experimental verification at the LHC or future colliders.A minimal extension of the Standard Model (SM) is proposed, where observed left-handed neutrinos obtain naturally small Majorana masses through a one-loop radiative seesaw mechanism. This model has two dark matter candidates: a bosonic and a fermionic particle. It has a simple structure and is verifiable in experiments at the Large Hadron Collider (LHC). In the canonical seesaw mechanism, heavy Majorana neutrinos are added to the SM to generate small neutrino masses. However, these particles are too heavy to be observed. In contrast, the one-loop mechanism involves lighter particles that may be detectable at the LHC. The model introduces a second scalar doublet and three heavy neutral fermion singlets under an exact Z2 symmetry. This symmetry ensures the lightest stable particle (LSP) is either the lighter component of the scalar doublet or the lightest neutrino. The model predicts dark matter candidates, either the lightest neutrino or the lighter scalar particle. The Yukawa interactions and scalar terms allow for the one-loop radiative generation of neutrino masses. The resulting neutrino mass matrix is calculated using the exchange of scalar particles, leading to a seesaw scale reduced by a factor of λ5/16π². Assuming λ5 ~ 10⁻⁴, the seesaw scale is reduced from 10⁹ GeV to ~1 TeV, making it experimentally accessible. The model also predicts observable decays of dark matter particles, allowing for the extraction of Yukawa couplings and verification of the seesaw mechanism. The scalar particles can be produced via SM gauge bosons and their decays can produce neutrinos. The model is suitable for studying lepton family symmetry and can incorporate tribimaximal mixing with tetrahedral symmetry. In conclusion, this minimal extension of the SM provides a framework for realistic neutrino masses and dark matter candidates, with potential experimental verification at the LHC or future colliders.