A field experiment was conducted to estimate potassium (K) and yield losses by Chenopodium album in wheat under different competition periods. The study consisted of zero competition, competition for 3.4,5,6,7,8 weeks after emergence (WAE), and for full season. Potassium concentration in C. album was maximum (4.91%) when it was allowed to compete with wheat for 6 WAE. Full season competition resulted in a maximum K uptake (8.22 kg ha-1) by C. album. Maximum K concentration (4.39%) in wheat was recorded in 4 WAE competition period whereas maximum K uptake (98.40 kg ha-1) by wheat was in full season competition period. There was a linear increase in dry wheat of C. album with increase in competition period. Grain yield decreased significantly beyond 3-4 WAE competition periods and maximum decrease (25.59%) in grain yield was observed in full season competition.