Comparison supports the development of children’s analogical reasoning. The evidence for this claim comes from laboratory studies. We describe spontaneous comparisons produced by 24 typically developing children from 26 to 58 months. Children tend to express similarity before expressing difference. They compare objects from the same category before objects from different categories, make global comparisons before specific comparisons, and specify perceptual features of similarity/difference before non-perceptual features. We then investigate how a theoretically interesting subset of children’s comparisons – those expressing a specific feature of similarity or difference – relates to analogical reasoning as measured by verbal and non-verbal tests in 6th grade. The number of specific comparisons children produce before 58 months predicts their scores on both tests, controlling for vocabulary at 54 months. The results provide naturalistic support for experimental findings on comparison development, and demonstrate a strong relationship between children’s early comparisons and their later analogical reasoning.