* Know the conversion: 1 kilogram (kg) = 1,000,000 milligrams (mg)

* Set up a proportion: (0.019 kg) / (x mg) = (1 kg) / (1,000,000 mg)

* Solve for x: Cross-multiply to get 0.019 kg * 1,000,000 mg = 1 kg * x mg

* Simplify: 19,000 mg = x mg

Therefore, there are 19,000 milligrams in 0.019 kilograms.