The rotational spectra of singly substituted 13 C and 15 N isotopic species of vinyl cyanide have been studied in natural abundances between 64 and 351GHz. In combination with previous results, greatly improved spectroscopic parameters have been obtained which in turn helped to identify transitions of the 13 C species for the first time in space through a molecular line survey of the extremely line-rich interstellar source Sagittarius B2(N) in the 3mm region with some additional observations at 2mm. The 13 C species are detected in two compact (∼2.3″), hot (170K) cores with a column density of ∼3.8×1016 and 1.1×1016cm-2, respectively. In the main source, the so-called “Large Molecule Heimat”, we derive an abundance of 2.9×10-9 for each 13 C species relative to H 2 . An isotopic ratio 12 C/ 13 C of 21 has been measured. Based on a comparison to the column densities measured for the 13 C species of ethyl cyanide also detected in this survey, it is suggested that the two hot cores of Sgr B2(N) are in different evolutionary stages. Supplementary laboratory data for the main isotopic species recorded between 92 and 342GHz permitted an improvement of its spectroscopic parameters as well.