Differential UBVRl photometry of the double-lined BY Dra system HD 80715 (K3 V + K3 V) obtained in December 1987 is presented. We found the star to be a variable with a full amplitude of 0.06 mag in V and a period similar or equal to the orbital period of 3.804 days. We interpret the mechanism of the variability as rotational modulation due to dark starspots. In an attempt to detect chromospheric activity we obtained high-resolution CCD spectra at Ca il H and K and at Fe I 6430 A and Ca I 6439 A, the photospheric lines normally used for Doppler imaging. HD 80715 shows double H and K emission features at a flux level of log S^H + K) « 6.7 erg cm -2 s -1 for each component. Observations of 11 LMi as a standard star suggest that it was constant within the uncertainties of our photometry during December 1987.

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