To provide an oil-based pesticidal suspension which suppresses foaming at the time of preparation of a spray liquid by an organic silicone type surfactant, and which has excellent pesticidal activity with a small amount of an agricultural chemical.The present invention provides an oil-based pesticidal suspension comprising (1) flonicamid or its salt, (2) an organic silicone type surfactant and (3) at least one oil-based diluting agent selected from the group consisting of a vegetable oil and its alkylated oil, and a method for controlling pests, which comprises applying the oil-based pesticidal suspension to the pests or to a place where they grow.