Just merged Excel write feature in master branch.
julia> import DataFrames, XLSX
julia> df = DataFrames.DataFrame(:integers=>[1, 2, 3, 4], :strings=>["Hey", "You", "Out", "There"], :floats=>[10.2, 20.3, 30.4, 40.5], :dates=>[Date(2018,2,20), Date(2018,2,21), Date(2018,2,22), Date(2018,2,23)], :times=>[Dates.Time(19,10), Dates.Time(19,20), Dates.Time(19,30), Dates.Time(19,40)], :datetimes=>[Dates.DateTime(2018,5,20,19,10), Dates.DateTime(2018,5,20,19,20), Dates.DateTime(2018,5,20,19,30), Dates.DateTime(2018,5,20,19,40)])
4×6 DataFrames.DataFrame
│ Row │ integers │ strings │ floats │ dates │ times │ datetimes │
├─────┼──────────┼─────────┼────────┼────────────┼──────────┼─────────────────────┤
│ 1 │ 1 │ Hey │ 10.2 │ 2018-02-20 │ 19:10:00 │ 2018-05-20T19:10:00 │
│ 2 │ 2 │ You │ 20.3 │ 2018-02-21 │ 19:20:00 │ 2018-05-20T19:20:00 │
│ 3 │ 3 │ Out │ 30.4 │ 2018-02-22 │ 19:30:00 │ 2018-05-20T19:30:00 │
│ 4 │ 4 │ There │ 40.5 │ 2018-02-23 │ 19:40:00 │ 2018-05-20T19:40:00 │
julia> XLSX.writetable("df.xlsx", DataFrames.columns(df), DataFrames.names(df))