The present invention relates to an aqueous conditioning serum. Despite the prior art there remains the need for improved serum conditioners. Accordingly, the present invention provides a visually clear aqueous conditioning serum for the hair comprising: 50 to 95% wt. water, 0.1 to 8% wt. silicone microemulsion, 5 to 15% wt. copolymer of ethylene glycol and propylene glycol according to one of the following formula: HO(CH2CH2O)x(CH(CH3)CH2O)y(CH2CH2O)z H (I) HO(CH(CH3)CH2O)x(CHCH2O)y(CH2(CH3)CH2O)z H (II) with the mean value of y in the range from 10 to 60 and the values of x and z both in the range from 1 to 150, 0.5 to 1.5% wt. thickener. The composition according to the invention conditions the hair without depositing too much silicone. Accordingly, it reduces the risk of applying too much and leaving the hair feeling lank and greasy.