A method for determining whether a Chikungunya virus (CHIKV) nucleic acid sequence is present in a test sample comprising nucleic acids, the method comprising the steps of: (a) contacting nucleic acids of the test sample with a set of amplification oligonucleotides, wherein a first member of the set is up to 100 bases in length and the 3' terminal base sequence is SEQ ID NO:108, and wherein a second member of the set is up to 100 bases in length and complementary to at least 15 contiguous bases of an extension product of the first member of the set of amplification oligonucleotides when a polynucleotide consisting of SEQ ID NO:14 is the template in a template-dependent primer extension reaction; (b) performing an in vitro nucleic acid amplification reaction using nucleic acids of the test sample as templates together with the set of amplification oligonucleotides, whereby, if the test sample comprises the CHIKV nucleic acid sequence, there is produced an amplification product; and (c) detecting any of the amplification product that may have been produced in the in vitro nucleic acid amplification reaction, wherein detecting the amplification product in an amount greater than a cutoff value indicates that the CHIKV nucleic acid sequence is present in the test sample, and wherein detecting the amplification product in an amount less than the cutoff value indicates that the CHIKV nucleic acid sequence is absent from the test sample. (a) contacting nucleic acids of the test sample with a set of amplification oligonucleotides, wherein a first member of the set is up to 100 bases in length and the 3' terminal base sequence is SEQ ID NO:108, and wherein a second member of the set is up to 100 bases in length and complementary to at least 15 contiguous bases of an extension product of the first member of the set of amplification oligonucleotides when a polynucleotide consisting of SEQ ID NO:14 is the template in a template-dependent primer extension reaction; wherein a first member of the set is up to 100 bases in length and the 3' terminal base sequence is SEQ ID NO:108, and wherein a second member of the set is up to 100 bases in length and complementary to at least 15 contiguous bases of an extension product of the first member of the set of amplification oligonucleotides when a polynucleotide consisting of SEQ ID NO:14 is the template in a template-dependent primer extension reaction; (b) performing an in vitro nucleic acid amplification reaction using nucleic acids of the test sample as templates together with the set of amplification oligonucleotides, whereby, if the test sample comprises the CHIKV nucleic acid sequence, there is produced an amplification product; and (c) detecting any of the amplification product that may have been produced in the in vitro nucleic acid amplification reaction, wherein detecting the amplification product in an amount greater than a cutoff value indicates that the CHIKV nucleic acid sequence is present in the test sample, and wherein detecting the amplification product in an amount less than the cutoff value indicates that the CHIKV nucleic acid sequence is absent from the test sample. wherein detecting the amplification product in an amount greater than a cutoff value indicates that the CHIKV nucleic acid sequence is present in the test sample, and wherein detecting the amplification product in an amount less than the cutoff value indicates that the CHIKV nucleic acid sequence is absent from the test sample.