We report on the growth and characterization of single crystals of Rb-Fe-Se system with varying stoichiometry prepared by self-flux and Bridgman methods. The results of the structural study by X-ray powder diffraction, Squid magnetometry, conductivity, and specific heat are presented [1]. The composition of the samples was measured by the wave-length dispersive electron-probe microanalysis. Rb1-xFe2-ySe2 single crystals exhibits a strongly anisotropic antiferromagnetic behavior below 400 K. For the range of Fe concentration 1.53 <2-y< 1.6 the superconducting (SC) behavior at low temperatures is also found. X-ray diffraction pattren of the superconducting samples is compartible with the tetragonal symmetry I4/m. The sharp transition into the superconducting state at Tc of 32.4 K is observed for compositions close to Rb0.8Fe1.6Se2. A critical current density jc of 1.6x104 A/cm2 (at 2 K) is reached in the superconducting samples with the highest diamagnetic response. The upper critical felds Hc2 of 250 kOe for the in-plane and 630 kOe for the inter-plane confgurations are estimated from the resistivity studies in magnetic felds parallel and perpendicular to the c-axis, respectively. The specific heat studies of the superconducting samples revealed a noticeable anomaly at the transition into the SC state indicating bulk superconductivity. However, the observed magnitude of the jump of the specific heat at Tc is about 5 times lower than in the superconducting FeSe0.5Te0.5 single crystals [2] suggesting lower volume fraction of the SC phase. In the powdered superconducting samples beside the reflexes of the tetragonal phase I4/m, additional x-ray reflexes appear, which show continuous growth with time at the expence of the suppressed main tetragonal phase. This process is accompanied by suppression of the antiferromagnetic behavior while the superconducting phase survives on a background of continuously increasing paramagnetic-like contribution. For the Fe concentrations below 1.5 and above 1.6, respectively, samples show insulating and semiconducting behavior. In the nonsuperconducting samples with the Fe concentration below 1.45 both specific heat and susceptibility revealed anomalies at 220 K which are not related to magnetic or structural transformations. Comparison of the magnetic behavior of superconducting and non-superconducting samples provides an evidence for the coexistence of superconductivity and static antiferromagnetic order. The evolution of the superconducting and antiferromagnetic correlations in the Rb-Fe-Se system is discussed within the constructed phase diagramm which includes several structural phases with different magnetic behavior. The coexistence of the superconductivity and antiferromagnetism in the Rb0.8Fe1.6Se2 single crystals is considered within a scenario of phase separation which is based on the recent results of neutron scattering [3,4], Mössbauer spectroscopy [5], optical and μSR [6,7], and nuclear magnetic resonance investigations [8] of these compounds.