Speckle interferometric observations made with the 6 m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences in 2000 revealed the triple nature of the nearby ( \pi _ { Hip } = 51.80 \pm 1.74 mas ) low-mass young ( \approx 200 Myr ) star GJ 900 . The configuration of the triple system allowed it to be dynamically unstable . Differential photometry performed from 2000 through 2004 yielded I - and K -band absolute magnitudes and spectral types for the components to be I _ { A } =6.66 \pm 0.08 , I _ { B } =9.15 \pm 0.11 , I _ { C } =10.08 \pm 0.26 , K _ { A } =4.84 \pm 0.08 , K _ { B } =6.76 \pm 0.20 , K _ { C } =7.39 \pm 0.31 , Sp _ { A } \approx K5–K7 , Sp _ { B } \approx M3–M4 , Sp _ { C } \approx M5–M6 . The “ mass–luminosity ” relation is used to estimate the individual masses of the components : \mathcal { M } _ { A } \approx 0.64 \mathcal { M } _ { \odot } , \mathcal { M } _ { B } \approx 0.21 \mathcal { M } _ { \odot } , \mathcal { M } _ { C } \approx 0.13 \mathcal { M } _ { \odot } . From the observations of the components relative motion in the period 2000–2006 , we conclude that GJ 900 is a hierarchical triple star with the possible orbital periods P _ { A - BC } \approx 80 yrs and P _ { BC } \approx 20 yrs . An analysis of the 2MASS images of the region around GJ 900 leads us to suggest that the system can include other very-low-mass components .