The pharmaceutically active compound atenolol, a kind of β-blockers, may result in adverse effects both for human health and ecosystems if it is excreted to the surface waters resources. To effectively remove atenolol in the environment, photodegradation, both direct and indirect, driven by sunlight is likely to play an important role. Among indirect photodegradation, singlet oxygen (1O2), as a pivotal reactive species, is likely to determine the fates of atenolol. Nevertheless, the kinetic information on the reaction of atenolol with singlet oxygen has not well been investigated and the reaction rate constant is still ambiguous. Herein, the reaction rate constant of atenolol with singlet oxygen is investigated directly through observing the decay of the 1O2 phosphorescence at 1270 nm. It is determined that the reaction rate constant between atenolol and 1O2 is 7.0×105 M-1 s-1 in D2O, 8.0×106 M-1 s-1 in ACN and 8.4×105 M-1 s-1 in EtOH, respectively. Furthermore, the solvent effects on the title reaction was also investigated. It is revealed that the solvents with strong polarity and weak hydrogen donating ability are suitable to achieve high rate constant values. These kinetics information on the reaction of atenolol with singlet oxygen may provide fundamental knowledge to the indirect photodegradation of β-blockers.