Lead-free sealing glasses possessing low melting temperature, high water durability, low thermal expansion coefficient, and high fluidity are desirable for sealing processes in the ceramics and electronics fields. In this paper, novel sealing glasses composed of metal and non-metal oxides (V2O5, MnO2 and KPO3) were developed, and their thermal properties, water durability, structure by X-ray or FT-IR analysis, fluidity by flow-button test, lightness by the Munsell value, sealing properties, and bonding strength by tension test were examined in detail. The glasses with low melting point and high fluidity were composed of 40 mol% V2O5-10 mol% MnO2-50 mol% KPO3, 30 mol% V2O5-20 mol% MnO2-50 mol% KPO3, or 30 mol% V2O5-10 mol% MnO2-60 mol% KPO3. However, these glasses with high phosphorus content had poor water durability, which could be improved considerably by the addition of CuO. The thermal expansion coefficients of the glasses were much higher than that of a soda lime glass (7-8x10(-6)degrees C-1) and were lowered to the level of a soda lime glass by the addition of a low thermal expansion ceramic filler (Zr-2(WO4)(PO4)(2), ZWP). Glass composed of 40 mol% V2O5-10 mol% MnO2-50 mol% KPO3 containing 20 wt% ZWP had an excellent sealing property comparable to commercial lead glass.