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Metasurfaces are nanostructured devices composed of arrays of subwavelength scatterers (or meta-atoms) that manipulate the wavefront, polarization, or intensity of light. Like most other diffractive optical devices, metasurfaces are designed to operate optimally at one wavelength. Here, we present a method for designing multiwavelength metasurfaces using unit cells with multiple meta-atoms, or meta-molecules. A transmissive lens that has the same focal distance at 1550 and 915 nm is demonstrated. The lens has a NA of 0.46 and measured focusing efficiencies of 65% and 22% at 1550 and 915 nm, respectively. With proper scaling, these devices can be used in applications where operation at distinct known wavelengths is required, like various fluorescence microscopy techniques.