Radiation from narrow circumferential slots on a conducting circular cylinder is analyzed. The incident TM01 mode is assumed to propagate along a thick conducting cylinder multiply slotted in the axial direction. The Fourier transform and mode matching are utilized to obtain a set of simultaneous equations for the discrete modal coefficients. Simple, fast convergent series solutions are presented using residue calculus. The radiation, transmission, and reflection characteristics are investigated in terms of the operating frequency and slot geometry. Our numerical results agree favorably with other existing data as well as measurements at X-band.