Disclosed are methods for detecting or quantifying one or more target polynucleotide sequences in a sample. In one aspect, a sample is contacted with first and second probe pair that are capable of hybridizing to a selected target sequence and a corresponding complementary sequence, respectively. Probe cleavage and ligation results in the formation of ligation products which can be generated in an exponential fashion when the target sequence and/or complement are present in the sample. In another embodiment, a single probe pair can be used to form ligation product in a linear fashion from a complementary template. Reagents and kits are also disclosed.